Common Weakness Enumeration

CWE-284

Discouraged

Improper Access Control

Abstraction: Pillar · Status: Incomplete

API response cwe.mitre.org

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

7801 vulnerabilities reference this CWE, most recent first.

GHSA-VFVF-8C7H-CPVH

Vulnerability from github – Published: 2026-03-26 15:30 – Updated: 2026-03-26 15:30
VLAI
Details

A vulnerability was determined in itsourcecode Free Hotel Reservation System 1.0. The affected element is an unknown function of the file /admin/mod_amenities/index.php?view=add. This manipulation of the argument image causes unrestricted upload. The attack is possible to be carried out remotely. The exploit has been publicly disclosed and may be utilized.

Severity
4.7 (Medium)
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
2.0 (Low)
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
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{
  "affected": [],
  "aliases": [
    "CVE-2026-4875"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-26T13:16:30Z",
    "severity": "MODERATE"
  },
  "details": "A vulnerability was determined in itsourcecode Free Hotel Reservation System 1.0. The affected element is an unknown function of the file /admin/mod_amenities/index.php?view=add. This manipulation of the argument image causes unrestricted upload. The attack is possible to be carried out remotely. The exploit has been publicly disclosed and may be utilized.",
  "id": "GHSA-vfvf-8c7h-cpvh",
  "modified": "2026-03-26T15:30:40Z",
  "published": "2026-03-26T15:30:40Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4875"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bybinyu/Vulnerability-Practice/issues/4"
    },
    {
      "type": "WEB",
      "url": "https://itsourcecode.com"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?ctiid.353558"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?id.353558"
    },
    {
      "type": "WEB",
      "url": "https://vuldb.com/?submit.776245"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

GHSA-VFWW-FWCC-XCP7

Vulnerability from github – Published: 2026-07-03 21:31 – Updated: 2026-07-03 21:31
VLAI
Details

Improper access control in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform spoofing over a network.

Severity
8.1 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:L
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-58282"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-03T21:17:02Z",
    "severity": "HIGH"
  },
  "details": "Improper access control in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform spoofing over a network.",
  "id": "GHSA-vfww-fwcc-xcp7",
  "modified": "2026-07-03T21:31:39Z",
  "published": "2026-07-03T21:31:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-58282"
    },
    {
      "type": "WEB",
      "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58282"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:L",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VG67-CHM7-8M3J

Vulnerability from github – Published: 2024-08-01 15:32 – Updated: 2025-07-09 17:51
VLAI
Summary
Mattermost allows remote actor to create/update/delete posts in arbitrary channels
Details

Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to properly validate synced posts, when shared channels are enabled,  which allows a malicious remote to create/update/delete arbitrary posts in arbitrary channels

Severity
5.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:L
7.0 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.5.0"
            },
            {
              "fixed": "9.5.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.7.0"
            },
            {
              "fixed": "9.7.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.8.0"
            },
            {
              "fixed": "9.8.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.9.0"
            },
            {
              "fixed": "9.9.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "9.9.0"
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0.0-20240619142046-8181a9ddffc0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.3.2-0.20240619142046-8181a9ddffc0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2024-41144"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-08-02T01:19:26Z",
    "nvd_published_at": "2024-08-01T15:15:13Z",
    "severity": "HIGH"
  },
  "details": "Mattermost versions 9.9.x \u003c= 9.9.0, 9.5.x \u003c= 9.5.6, 9.7.x \u003c= 9.7.5, 9.8.x \u003c= 9.8.1 fail to properly validate\u00a0synced posts, when shared channels are enabled,\u00a0\u00a0which allows a malicious remote to create/update/delete arbitrary posts in arbitrary channels",
  "id": "GHSA-vg67-chm7-8m3j",
  "modified": "2025-07-09T17:51:06Z",
  "published": "2024-08-01T15:32:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-41144"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mattermost/mattermost"
    },
    {
      "type": "WEB",
      "url": "https://mattermost.com/security-updates"
    },
    {
      "type": "WEB",
      "url": "https://pkg.go.dev/vuln/GO-2024-3023"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Mattermost allows remote actor to create/update/delete posts in arbitrary channels"
}

GHSA-VG6F-74HF-WXFG

Vulnerability from github – Published: 2022-05-17 02:50 – Updated: 2022-05-17 02:50
VLAI
Details

Cougar-LG stores sensitive information under the web root with insufficient access control, which allows remote attackers to obtain credentials.

Severity
9.8 (Critical)
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2014-3928"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2017-04-03T15:59:00Z",
    "severity": "CRITICAL"
  },
  "details": "Cougar-LG stores sensitive information under the web root with insufficient access control, which allows remote attackers to obtain credentials.",
  "id": "GHSA-vg6f-74hf-wxfg",
  "modified": "2022-05-17T02:50:44Z",
  "published": "2022-05-17T02:50:44Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2014-3928"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Cougar/lg/issues/4"
    },
    {
      "type": "WEB",
      "url": "https://hackerone.com/reports/16330"
    },
    {
      "type": "WEB",
      "url": "http://www.s3.eurecom.fr/cve/CVE-2014-3928.txt"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VG6Q-84P8-QVQH

Vulnerability from github – Published: 2024-08-01 15:32 – Updated: 2024-08-07 19:33
VLAI
Summary
Mattermost allows a user on a remote to set their remote username prop to an arbitrary string
Details

Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the local server as long as the user hadn't been synced before.

Severity
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
5.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.5.0"
            },
            {
              "fixed": "9.5.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.7.0"
            },
            {
              "fixed": "9.7.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.8.0"
            },
            {
              "fixed": "9.8.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.9.0"
            },
            {
              "fixed": "9.9.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "9.9.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2024-39839"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-08-02T01:18:32Z",
    "nvd_published_at": "2024-08-01T15:15:12Z",
    "severity": "MODERATE"
  },
  "details": "Mattermost versions 9.9.x \u003c= 9.9.0, 9.5.x \u003c= 9.5.6, 9.7.x \u003c= 9.7.5, 9.8.x \u003c= 9.8.1 fail to disallow\u00a0users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the local server as long as the user hadn\u0027t been synced before.",
  "id": "GHSA-vg6q-84p8-qvqh",
  "modified": "2024-08-07T19:33:19Z",
  "published": "2024-08-01T15:32:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-39839"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mattermost/mattermost"
    },
    {
      "type": "WEB",
      "url": "https://mattermost.com/security-updates"
    },
    {
      "type": "WEB",
      "url": "https://pkg.go.dev/vuln/GO-2024-3024"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Mattermost allows a user on a remote to set their remote username prop to an arbitrary string"
}

GHSA-VG84-CXX6-3J79

Vulnerability from github – Published: 2024-09-02 00:30 – Updated: 2024-09-03 18:31
VLAI
Details

Linen before cd37c3e does not verify that the domain is linen.dev or www.linen.dev when resetting a password. This occurs in create in apps/web/pages/api/forgot-password/index.ts.

Severity
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2024-45522"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-09-02T00:15:11Z",
    "severity": "CRITICAL"
  },
  "details": "Linen before cd37c3e does not verify that the domain is linen.dev or www.linen.dev when resetting a password. This occurs in create in apps/web/pages/api/forgot-password/index.ts.",
  "id": "GHSA-vg84-cxx6-3j79",
  "modified": "2024-09-03T18:31:32Z",
  "published": "2024-09-02T00:30:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-45522"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Linen-dev/linen.dev/commit/cd37c3e88ec29f4e7baae7e32fe80d0137848d10"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VGGM-VVXJ-GGQ4

Vulnerability from github – Published: 2024-01-10 09:30 – Updated: 2024-01-17 03:30
VLAI
Details

Totolink N200RE_V5 V9.3.5u.6255_B20211224 is vulnerable to Incorrect Access Control. The device allows remote attackers to obtain Wi-Fi system information, such as Wi-Fi SSID and Wi-Fi password, without logging into the management page.

Severity
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2022-46025"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-01-10T08:15:37Z",
    "severity": "CRITICAL"
  },
  "details": "Totolink N200RE_V5 V9.3.5u.6255_B20211224 is vulnerable to Incorrect Access Control. The device allows remote attackers to obtain Wi-Fi system information, such as Wi-Fi SSID and Wi-Fi password, without logging into the management page.",
  "id": "GHSA-vggm-vvxj-ggq4",
  "modified": "2024-01-17T03:30:55Z",
  "published": "2024-01-10T09:30:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-46025"
    },
    {
      "type": "WEB",
      "url": "https://pastebin.com/aan5jT40"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VGMW-9CWW-QQ99

Vulnerability from github – Published: 2022-01-31 00:00 – Updated: 2024-11-18 16:26
VLAI
Summary
Incorrect Authorization in calibreweb
Details

calibreweb prior to version 0.6.16 contains an Incorrect Authorization vulnerability.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
7.1 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "calibreweb"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.6.16"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2022-0273"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284",
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-02-07T21:14:46Z",
    "nvd_published_at": "2022-01-30T14:15:00Z",
    "severity": "HIGH"
  },
  "details": "calibreweb prior to version 0.6.16 contains an Incorrect Authorization vulnerability.",
  "id": "GHSA-vgmw-9cww-qq99",
  "modified": "2024-11-18T16:26:18Z",
  "published": "2022-01-31T00:00:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-0273"
    },
    {
      "type": "WEB",
      "url": "https://github.com/janeczku/calibre-web/commit/0c0313f375bed7b035c8c0482bbb09599e16bfcf"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/janeczku/calibre-web"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/calibreweb/PYSEC-2022-22.yaml"
    },
    {
      "type": "WEB",
      "url": "https://huntr.dev/bounties/8f27686f-d698-4ab6-8ef0-899125792f13"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Incorrect Authorization in calibreweb"
}

GHSA-VGQ4-3X26-93JQ

Vulnerability from github – Published: 2024-03-08 03:31 – Updated: 2026-04-02 21:31
VLAI
Details

The issue was addressed with improved checks. This issue is fixed in macOS Sonoma 14.4, macOS Monterey 12.7.4, macOS Ventura 13.6.5. An app may be able to bypass certain Privacy preferences.

Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2024-23267"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-03-08T02:15:49Z",
    "severity": "MODERATE"
  },
  "details": "The issue was addressed with improved checks. This issue is fixed in macOS Sonoma 14.4, macOS Monterey 12.7.4, macOS Ventura 13.6.5. An app may be able to bypass certain Privacy preferences.",
  "id": "GHSA-vgq4-3x26-93jq",
  "modified": "2026-04-02T21:31:38Z",
  "published": "2024-03-08T03:31:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-23267"
    },
    {
      "type": "WEB",
      "url": "https://support.apple.com/en-us/120884"
    },
    {
      "type": "WEB",
      "url": "https://support.apple.com/en-us/120886"
    },
    {
      "type": "WEB",
      "url": "https://support.apple.com/en-us/120895"
    },
    {
      "type": "WEB",
      "url": "https://support.apple.com/en-us/HT214083"
    },
    {
      "type": "WEB",
      "url": "https://support.apple.com/en-us/HT214084"
    },
    {
      "type": "WEB",
      "url": "https://support.apple.com/en-us/HT214085"
    },
    {
      "type": "WEB",
      "url": "https://support.apple.com/kb/HT214083"
    },
    {
      "type": "WEB",
      "url": "https://support.apple.com/kb/HT214084"
    },
    {
      "type": "WEB",
      "url": "https://support.apple.com/kb/HT214085"
    },
    {
      "type": "WEB",
      "url": "http://seclists.org/fulldisclosure/2024/Mar/21"
    },
    {
      "type": "WEB",
      "url": "http://seclists.org/fulldisclosure/2024/Mar/22"
    },
    {
      "type": "WEB",
      "url": "http://seclists.org/fulldisclosure/2024/Mar/23"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VGRC-HQ28-P3XP

Vulnerability from github – Published: 2026-06-26 19:48 – Updated: 2026-06-26 19:48
VLAI
Summary
Hysteria has an authenticated UDP ACL bypass that enables localhost and private-network UDP SSRF
Details

Summary

Hysteria's UDP relay treats the destination address as packet-scoped, but ACL and outbound policy are applied only once when a new UDP session is created. After an authenticated client opens a UDP session using an allowed first destination, later packets in the same Session ID can be sent to different destinations without re-running ACL evaluation.

This allows an authenticated user to bypass server-side UDP ACL rules and reach localhost or RFC1918/private-network UDP services from the server's network perspective, even when those destinations are explicitly rejected by ACL.

Verified on current HEAD at commit 64c396385631579598cc29d5561bff98c439772f.

Why this is a security issue

This report is not based on the assumption that one UDP session must be bound to one destination. The protocol and official client both support per-packet destinations:

  • PROTOCOL.md:93-107 defines each UDPMessage as carrying its own Addr field.
  • core/client/udp.go:52-62 exposes Send(data, addr), allowing the same UDP session to send to arbitrary addresses.

The problem is that the security-relevant destination is packet-scoped, while ACL and outbound authorization are cached at session scope.

This is also not a RequestHook-bypass claim. I understand RequestHook is first-packet-oriented. The broader issue is that operator-configured ACL policy intended to block UDP destinations is not enforced on later packets within the same session.

Because the ACL documentation is presented as the mechanism for handling or blocking client requests, and includes examples of denying udp/443 and private network CIDRs, operators can reasonably rely on ACL as a UDP egress security boundary. This boundary can currently be bypassed by reusing a previously authorized UDP session.

Root cause

The relevant flow appears to be:

  • core/server/udp.go:280-299: when a new session is created, the first destination is passed through m.io.Hook(...), logged, and then m.io.UDP(addr) is called once to create the outbound UDP connection.
  • core/server/server.go:397-398: m.io.UDP(addr) delegates to io.Outbound.UDP(reqAddr).
  • app/cmd/server.go:1187-1190: resolver, ACL, and actual outbounds are intentionally chained through the Outbound interface.
  • core/server/udp.go:125: the initial outbound connection is created only from the first packet via DialFunc(firstMsg.Addr, firstMsg.Data).
  • core/server/udp.go:92-111: later packets in the same session take the current packet address and directly call e.conn.WriteTo(dfMsg.Data, addr) without re-running ACL or outbound policy evaluation.

In other words, destination selection is packet-scoped, but authorization is session-scoped.

Impact

Any authenticated client that is allowed to use UDP relay can:

  • open one UDP session using an allowed first destination;
  • reuse the same session to send packets to destinations that ACL should reject;
  • reach UDP services on 127.0.0.1 or on RFC1918/private-network addresses from the server's network perspective.

In real deployments, this can expose internal-only UDP services such as:

  • internal DNS resolvers;
  • service discovery endpoints;
  • telemetry or metrics listeners;
  • local administrative daemons;
  • application-specific UDP services intended to be reachable only from localhost or the internal network.

This breaks the server's documented ACL-based UDP egress restrictions.

Reproduction

Two cases were reproduced with integration tests.

Case 1: localhost bypass

ACL:

direct(127.0.0.1, udp/<allowedPort>)
reject(127.0.0.1/32)

Steps:

  1. Start one UDP echo service on 127.0.0.1:<allowedPort>.
  2. Start another UDP echo service on 127.0.0.1:<blockedPort>.
  3. Connect an authenticated Hysteria client and create one UDP session.
  4. Send a packet to the allowed loopback destination to establish the session.
  5. Reuse the same UDP session and send a packet to the blocked loopback destination.

Observed result:

  • The second packet is relayed successfully and the blocked loopback service replies.

Expected result:

  • The second packet should be rejected because 127.0.0.1/32 is denied by ACL.

Case 2: private-network bypass

ACL:

direct(127.0.0.1, udp/<allowedPort>)
reject(10.0.0.0/8)

or the corresponding local RFC1918 range, such as 192.168.0.0/16 or 172.16.0.0/12.

Steps:

  1. Start one UDP echo service on 127.0.0.1:<allowedPort>.
  2. Start another UDP echo service on a real RFC1918 address of the server host.
  3. Connect an authenticated Hysteria client and create one UDP session.
  4. Send a packet to the allowed loopback destination first.
  5. Reuse the same UDP session and send a packet to the RFC1918 destination.

Observed result:

  • The private-address packet is relayed successfully and receives a reply.

Expected result:

  • The packet should be rejected by ACL.

PoC and local evidence

A local integration test file was added during verification:

  • core/internal/integration_tests/udp_private_acl_bypass_test.go

The two tests are:

  • TestClientServerUDPACLBYPASSLoopback
  • TestClientServerUDPACLBYPASSPrivateIPv4

They can be executed with:

go test ./core/internal/integration_tests -run 'TestClientServerUDPACLBYPASS(Loopback|PrivateIPv4)' -count=1

The tests pass locally and demonstrate that a destination blocked by ACL becomes reachable after the session is established with an allowed first destination.

Suggested fixes

Any of the following would address the issue:

  1. Re-evaluate ACL and outbound policy for every defragmented UDP packet before forwarding it with WriteTo.
  2. Alternatively, enforce a single immutable destination per UDP session and reject destination changes after the first packet.
  3. Ensure logging and policy hooks are aligned with the chosen model so that policy enforcement and observability reflect the real per-packet destination.

Severity assessment

Suggested CVSS v3.1 vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L

This reflects a network-reachable issue with low attack complexity, requiring only an authenticated client, no victim interaction, and allowing impact beyond the proxy process by exposing localhost and internal-network UDP resources from the server's trust boundary.

Severity
7.4 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.9.1"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/apernet/hysteria/core/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "2.9.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-284",
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-26T19:48:50Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "## Summary\n\nHysteria\u0027s UDP relay treats the destination address as packet-scoped, but ACL and outbound policy are applied only once when a new UDP session is created. After an authenticated client opens a UDP session using an allowed first destination, later packets in the same `Session ID` can be sent to different destinations without re-running ACL evaluation.\n\nThis allows an authenticated user to bypass server-side UDP ACL rules and reach localhost or RFC1918/private-network UDP services from the server\u0027s network perspective, even when those destinations are explicitly rejected by ACL.\n\nVerified on current HEAD at commit `64c396385631579598cc29d5561bff98c439772f`.\n\n## Why this is a security issue\n\nThis report is not based on the assumption that one UDP session must be bound to one destination. The protocol and official client both support per-packet destinations:\n\n- `PROTOCOL.md:93-107` defines each `UDPMessage` as carrying its own `Addr` field.\n- `core/client/udp.go:52-62` exposes `Send(data, addr)`, allowing the same UDP session to send to arbitrary addresses.\n\nThe problem is that the security-relevant destination is packet-scoped, while ACL and outbound authorization are cached at session scope.\n\nThis is also not a `RequestHook`-bypass claim. I understand `RequestHook` is first-packet-oriented. The broader issue is that operator-configured ACL policy intended to block UDP destinations is not enforced on later packets within the same session.\n\nBecause the ACL documentation is presented as the mechanism for handling or blocking client requests, and includes examples of denying `udp/443` and private network CIDRs, operators can reasonably rely on ACL as a UDP egress security boundary. This boundary can currently be bypassed by reusing a previously authorized UDP session.\n\n## Root cause\n\nThe relevant flow appears to be:\n\n- `core/server/udp.go:280-299`: when a new session is created, the first destination is passed through `m.io.Hook(...)`, logged, and then `m.io.UDP(addr)` is called once to create the outbound UDP connection.\n- `core/server/server.go:397-398`: `m.io.UDP(addr)` delegates to `io.Outbound.UDP(reqAddr)`.\n- `app/cmd/server.go:1187-1190`: resolver, ACL, and actual outbounds are intentionally chained through the `Outbound` interface.\n- `core/server/udp.go:125`: the initial outbound connection is created only from the first packet via `DialFunc(firstMsg.Addr, firstMsg.Data)`.\n- `core/server/udp.go:92-111`: later packets in the same session take the current packet address and directly call `e.conn.WriteTo(dfMsg.Data, addr)` without re-running ACL or outbound policy evaluation.\n\nIn other words, destination selection is packet-scoped, but authorization is session-scoped.\n\n## Impact\n\nAny authenticated client that is allowed to use UDP relay can:\n\n- open one UDP session using an allowed first destination;\n- reuse the same session to send packets to destinations that ACL should reject;\n- reach UDP services on `127.0.0.1` or on RFC1918/private-network addresses from the server\u0027s network perspective.\n\nIn real deployments, this can expose internal-only UDP services such as:\n\n- internal DNS resolvers;\n- service discovery endpoints;\n- telemetry or metrics listeners;\n- local administrative daemons;\n- application-specific UDP services intended to be reachable only from localhost or the internal network.\n\nThis breaks the server\u0027s documented ACL-based UDP egress restrictions.\n\n## Reproduction\n\nTwo cases were reproduced with integration tests.\n\n### Case 1: localhost bypass\n\nACL:\n\n```text\ndirect(127.0.0.1, udp/\u003callowedPort\u003e)\nreject(127.0.0.1/32)\n```\n\nSteps:\n\n1. Start one UDP echo service on `127.0.0.1:\u003callowedPort\u003e`.\n2. Start another UDP echo service on `127.0.0.1:\u003cblockedPort\u003e`.\n3. Connect an authenticated Hysteria client and create one UDP session.\n4. Send a packet to the allowed loopback destination to establish the session.\n5. Reuse the same UDP session and send a packet to the blocked loopback destination.\n\nObserved result:\n\n- The second packet is relayed successfully and the blocked loopback service replies.\n\nExpected result:\n\n- The second packet should be rejected because `127.0.0.1/32` is denied by ACL.\n\n### Case 2: private-network bypass\n\nACL:\n\n```text\ndirect(127.0.0.1, udp/\u003callowedPort\u003e)\nreject(10.0.0.0/8)\n```\n\nor the corresponding local RFC1918 range, such as `192.168.0.0/16` or `172.16.0.0/12`.\n\nSteps:\n\n1. Start one UDP echo service on `127.0.0.1:\u003callowedPort\u003e`.\n2. Start another UDP echo service on a real RFC1918 address of the server host.\n3. Connect an authenticated Hysteria client and create one UDP session.\n4. Send a packet to the allowed loopback destination first.\n5. Reuse the same UDP session and send a packet to the RFC1918 destination.\n\nObserved result:\n\n- The private-address packet is relayed successfully and receives a reply.\n\nExpected result:\n\n- The packet should be rejected by ACL.\n\n## PoC and local evidence\n\nA local integration test file was added during verification:\n\n- `core/internal/integration_tests/udp_private_acl_bypass_test.go`\n\nThe two tests are:\n\n- `TestClientServerUDPACLBYPASSLoopback`\n- `TestClientServerUDPACLBYPASSPrivateIPv4`\n\nThey can be executed with:\n\n```bash\ngo test ./core/internal/integration_tests -run \u0027TestClientServerUDPACLBYPASS(Loopback|PrivateIPv4)\u0027 -count=1\n```\n\nThe tests pass locally and demonstrate that a destination blocked by ACL becomes reachable after the session is established with an allowed first destination.\n\n## Suggested fixes\n\nAny of the following would address the issue:\n\n1. Re-evaluate ACL and outbound policy for every defragmented UDP packet before forwarding it with `WriteTo`.\n2. Alternatively, enforce a single immutable destination per UDP session and reject destination changes after the first packet.\n3. Ensure logging and policy hooks are aligned with the chosen model so that policy enforcement and observability reflect the real per-packet destination.\n\n## Severity assessment\n\nSuggested CVSS v3.1 vector: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L`\n\nThis reflects a network-reachable issue with low attack complexity, requiring only an authenticated client, no victim interaction, and allowing impact beyond the proxy process by exposing localhost and internal-network UDP resources from the server\u0027s trust boundary.",
  "id": "GHSA-vgrc-hq28-p3xp",
  "modified": "2026-06-26T19:48:50Z",
  "published": "2026-06-26T19:48:50Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/apernet/hysteria/security/advisories/GHSA-vgrc-hq28-p3xp"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/apernet/hysteria"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Hysteria has an authenticated UDP ACL bypass that enables localhost and private-network UDP SSRF"
}
Mitigation MIT-1
Architecture and Design Operation

Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.

Mitigation MIT-46
Architecture and Design

Strategy: Separation of Privilege

  • Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
  • Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
CAPEC-19: Embedding Scripts within Scripts

An adversary leverages the capability to execute their own script by embedding it within other scripts that the target software is likely to execute due to programs' vulnerabilities that are brought on by allowing remote hosts to execute scripts.

CAPEC-441: Malicious Logic Insertion

An adversary installs or adds malicious logic (also known as malware) into a seemingly benign component of a fielded system. This logic is often hidden from the user of the system and works behind the scenes to achieve negative impacts. With the proliferation of mass digital storage and inexpensive multimedia devices, Bluetooth and 802.11 support, new attack vectors for spreading malware are emerging for things we once thought of as innocuous greeting cards, picture frames, or digital projectors. This pattern of attack focuses on systems already fielded and used in operation as opposed to systems and their components that are still under development and part of the supply chain.

CAPEC-478: Modification of Windows Service Configuration

An adversary exploits a weakness in access control to modify the execution parameters of a Windows service. The goal of this attack is to execute a malicious binary in place of an existing service.

CAPEC-479: Malicious Root Certificate

An adversary exploits a weakness in authorization and installs a new root certificate on a compromised system. Certificates are commonly used for establishing secure TLS/SSL communications within a web browser. When a user attempts to browse a website that presents a certificate that is not trusted an error message will be displayed to warn the user of the security risk. Depending on the security settings, the browser may not allow the user to establish a connection to the website. Adversaries have used this technique to avoid security warnings prompting users when compromised systems connect over HTTPS to adversary controlled web servers that spoof legitimate websites in order to collect login credentials.

CAPEC-502: Intent Spoof

An adversary, through a previously installed malicious application, issues an intent directed toward a specific trusted application's component in an attempt to achieve a variety of different objectives including modification of data, information disclosure, and data injection. Components that have been unintentionally exported and made public are subject to this type of an attack. If the component trusts the intent's action without verififcation, then the target application performs the functionality at the adversary's request, helping the adversary achieve the desired negative technical impact.

CAPEC-503: WebView Exposure

An adversary, through a malicious web page, accesses application specific functionality by leveraging interfaces registered through WebView's addJavascriptInterface API. Once an interface is registered to WebView through addJavascriptInterface, it becomes global and all pages loaded in the WebView can call this interface.

CAPEC-536: Data Injected During Configuration

An attacker with access to data files and processes on a victim's system injects malicious data into critical operational data during configuration or recalibration, causing the victim's system to perform in a suboptimal manner that benefits the adversary.

CAPEC-546: Incomplete Data Deletion in a Multi-Tenant Environment

An adversary obtains unauthorized information due to insecure or incomplete data deletion in a multi-tenant environment. If a cloud provider fails to completely delete storage and data from former cloud tenants' systems/resources, once these resources are allocated to new, potentially malicious tenants, the latter can probe the provided resources for sensitive information still there.

CAPEC-550: Install New Service

When an operating system starts, it also starts programs called services or daemons. Adversaries may install a new service which will be executed at startup (on a Windows system, by modifying the registry). The service name may be disguised by using a name from a related operating system or benign software. Services are usually run with elevated privileges.

CAPEC-551: Modify Existing Service

When an operating system starts, it also starts programs called services or daemons. Modifying existing services may break existing services or may enable services that are disabled/not commonly used.

CAPEC-552: Install Rootkit

An adversary exploits a weakness in authentication to install malware that alters the functionality and information provide by targeted operating system API calls. Often referred to as rootkits, it is often used to hide the presence of programs, files, network connections, services, drivers, and other system components.

CAPEC-556: Replace File Extension Handlers

When a file is opened, its file handler is checked to determine which program opens the file. File handlers are configuration properties of many operating systems. Applications can modify the file handler for a given file extension to call an arbitrary program when a file with the given extension is opened.

CAPEC-558: Replace Trusted Executable

An adversary exploits weaknesses in privilege management or access control to replace a trusted executable with a malicious version and enable the execution of malware when that trusted executable is called.

CAPEC-562: Modify Shared File

An adversary manipulates the files in a shared location by adding malicious programs, scripts, or exploit code to valid content. Once a user opens the shared content, the tainted content is executed.

CAPEC-563: Add Malicious File to Shared Webroot

An adversaries may add malicious content to a website through the open file share and then browse to that content with a web browser to cause the server to execute the content. The malicious content will typically run under the context and permissions of the web server process, often resulting in local system or administrative privileges depending on how the web server is configured.

CAPEC-564: Run Software at Logon

Operating system allows logon scripts to be run whenever a specific user or users logon to a system. If adversaries can access these scripts, they may insert additional code into the logon script. This code can allow them to maintain persistence or move laterally within an enclave because it is executed every time the affected user or users logon to a computer. Modifying logon scripts can effectively bypass workstation and enclave firewalls. Depending on the access configuration of the logon scripts, either local credentials or a remote administrative account may be necessary.

CAPEC-578: Disable Security Software

An adversary exploits a weakness in access control to disable security tools so that detection does not occur. This can take the form of killing processes, deleting registry keys so that tools do not start at run time, deleting log files, or other methods.

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