ubuntu-cve-2026-6253
Vulnerability from osv_ubuntu
Published
2026-04-29 14:00
Modified
2026-07-10 00:02
Summary
Details

curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1. curl is setup to use specific different proxies for different URL schemes 2. the first proxy needs credentials 3. the second proxy uses no credentials 4. while using the first proxy (using say http://), curl is asked to follow a redirect to a URL using another scheme (say https://), accessed using a second, different, proxy

Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "curl",
            "binary_version": "7.35.0-1ubuntu2.20+esm21"
          },
          {
            "binary_name": "libcurl3",
            "binary_version": "7.35.0-1ubuntu2.20+esm21"
          },
          {
            "binary_name": "libcurl3-gnutls",
            "binary_version": "7.35.0-1ubuntu2.20+esm21"
          },
          {
            "binary_name": "libcurl3-nss",
            "binary_version": "7.35.0-1ubuntu2.20+esm21"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "curl",
        "purl": "pkg:deb/ubuntu/curl@7.35.0-1ubuntu2.20+esm21?arch=source\u0026distro=esm-infra-legacy/trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "7.32.0-1ubuntu1",
        "7.33.0-1ubuntu1",
        "7.34.0-1ubuntu1",
        "7.35.0-1ubuntu1",
        "7.35.0-1ubuntu2",
        "7.35.0-1ubuntu2.1",
        "7.35.0-1ubuntu2.2",
        "7.35.0-1ubuntu2.3",
        "7.35.0-1ubuntu2.5",
        "7.35.0-1ubuntu2.6",
        "7.35.0-1ubuntu2.7",
        "7.35.0-1ubuntu2.8",
        "7.35.0-1ubuntu2.9",
        "7.35.0-1ubuntu2.10",
        "7.35.0-1ubuntu2.11",
        "7.35.0-1ubuntu2.12",
        "7.35.0-1ubuntu2.13",
        "7.35.0-1ubuntu2.14",
        "7.35.0-1ubuntu2.15",
        "7.35.0-1ubuntu2.16",
        "7.35.0-1ubuntu2.17",
        "7.35.0-1ubuntu2.19",
        "7.35.0-1ubuntu2.20",
        "7.35.0-1ubuntu2.20+esm2",
        "7.35.0-1ubuntu2.20+esm3",
        "7.35.0-1ubuntu2.20+esm4",
        "7.35.0-1ubuntu2.20+esm5",
        "7.35.0-1ubuntu2.20+esm6",
        "7.35.0-1ubuntu2.20+esm7",
        "7.35.0-1ubuntu2.20+esm8",
        "7.35.0-1ubuntu2.20+esm9",
        "7.35.0-1ubuntu2.20+esm10",
        "7.35.0-1ubuntu2.20+esm11",
        "7.35.0-1ubuntu2.20+esm12",
        "7.35.0-1ubuntu2.20+esm13",
        "7.35.0-1ubuntu2.20+esm14",
        "7.35.0-1ubuntu2.20+esm15",
        "7.35.0-1ubuntu2.20+esm16",
        "7.35.0-1ubuntu2.20+esm17",
        "7.35.0-1ubuntu2.20+esm18",
        "7.35.0-1ubuntu2.20+esm19",
        "7.35.0-1ubuntu2.20+esm20",
        "7.35.0-1ubuntu2.20+esm21"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "curl",
            "binary_version": "7.47.0-1ubuntu2.19+esm17"
          },
          {
            "binary_name": "libcurl3",
            "binary_version": "7.47.0-1ubuntu2.19+esm17"
          },
          {
            "binary_name": "libcurl3-gnutls",
            "binary_version": "7.47.0-1ubuntu2.19+esm17"
          },
          {
            "binary_name": "libcurl3-nss",
            "binary_version": "7.47.0-1ubuntu2.19+esm17"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "curl",
        "purl": "pkg:deb/ubuntu/curl@7.47.0-1ubuntu2.19+esm17?arch=source\u0026distro=esm-infra-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "7.43.0-1ubuntu2",
        "7.45.0-1ubuntu1",
        "7.46.0-1ubuntu1",
        "7.47.0-1ubuntu1",
        "7.47.0-1ubuntu2",
        "7.47.0-1ubuntu2.1",
        "7.47.0-1ubuntu2.2",
        "7.47.0-1ubuntu2.3",
        "7.47.0-1ubuntu2.4",
        "7.47.0-1ubuntu2.5",
        "7.47.0-1ubuntu2.6",
        "7.47.0-1ubuntu2.7",
        "7.47.0-1ubuntu2.8",
        "7.47.0-1ubuntu2.9",
        "7.47.0-1ubuntu2.11",
        "7.47.0-1ubuntu2.12",
        "7.47.0-1ubuntu2.13",
        "7.47.0-1ubuntu2.14",
        "7.47.0-1ubuntu2.15",
        "7.47.0-1ubuntu2.16",
        "7.47.0-1ubuntu2.18",
        "7.47.0-1ubuntu2.19",
        "7.47.0-1ubuntu2.19+esm1",
        "7.47.0-1ubuntu2.19+esm2",
        "7.47.0-1ubuntu2.19+esm3",
        "7.47.0-1ubuntu2.19+esm4",
        "7.47.0-1ubuntu2.19+esm5",
        "7.47.0-1ubuntu2.19+esm6",
        "7.47.0-1ubuntu2.19+esm7",
        "7.47.0-1ubuntu2.19+esm8",
        "7.47.0-1ubuntu2.19+esm9",
        "7.47.0-1ubuntu2.19+esm10",
        "7.47.0-1ubuntu2.19+esm11",
        "7.47.0-1ubuntu2.19+esm12",
        "7.47.0-1ubuntu2.19+esm13",
        "7.47.0-1ubuntu2.19+esm15",
        "7.47.0-1ubuntu2.19+esm16",
        "7.47.0-1ubuntu2.19+esm17"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "curl",
            "binary_version": "7.58.0-2ubuntu3.24+esm10"
          },
          {
            "binary_name": "libcurl3-gnutls",
            "binary_version": "7.58.0-2ubuntu3.24+esm10"
          },
          {
            "binary_name": "libcurl3-nss",
            "binary_version": "7.58.0-2ubuntu3.24+esm10"
          },
          {
            "binary_name": "libcurl4",
            "binary_version": "7.58.0-2ubuntu3.24+esm10"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "curl",
        "purl": "pkg:deb/ubuntu/curl@7.58.0-2ubuntu3.24+esm10?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "7.55.1-1ubuntu2",
        "7.55.1-1ubuntu2.1",
        "7.57.0-1ubuntu1",
        "7.58.0-2ubuntu1",
        "7.58.0-2ubuntu2",
        "7.58.0-2ubuntu3",
        "7.58.0-2ubuntu3.1",
        "7.58.0-2ubuntu3.2",
        "7.58.0-2ubuntu3.3",
        "7.58.0-2ubuntu3.5",
        "7.58.0-2ubuntu3.6",
        "7.58.0-2ubuntu3.7",
        "7.58.0-2ubuntu3.8",
        "7.58.0-2ubuntu3.9",
        "7.58.0-2ubuntu3.10",
        "7.58.0-2ubuntu3.12",
        "7.58.0-2ubuntu3.13",
        "7.58.0-2ubuntu3.14",
        "7.58.0-2ubuntu3.15",
        "7.58.0-2ubuntu3.16",
        "7.58.0-2ubuntu3.17",
        "7.58.0-2ubuntu3.18",
        "7.58.0-2ubuntu3.19",
        "7.58.0-2ubuntu3.20",
        "7.58.0-2ubuntu3.21",
        "7.58.0-2ubuntu3.22",
        "7.58.0-2ubuntu3.23",
        "7.58.0-2ubuntu3.24",
        "7.58.0-2ubuntu3.24+esm1",
        "7.58.0-2ubuntu3.24+esm2",
        "7.58.0-2ubuntu3.24+esm3",
        "7.58.0-2ubuntu3.24+esm4",
        "7.58.0-2ubuntu3.24+esm5",
        "7.58.0-2ubuntu3.24+esm7",
        "7.58.0-2ubuntu3.24+esm8",
        "7.58.0-2ubuntu3.24+esm9",
        "7.58.0-2ubuntu3.24+esm10"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "curl",
            "binary_version": "7.68.0-1ubuntu2.25+esm5"
          },
          {
            "binary_name": "libcurl3-gnutls",
            "binary_version": "7.68.0-1ubuntu2.25+esm5"
          },
          {
            "binary_name": "libcurl3-nss",
            "binary_version": "7.68.0-1ubuntu2.25+esm5"
          },
          {
            "binary_name": "libcurl4",
            "binary_version": "7.68.0-1ubuntu2.25+esm5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "curl",
        "purl": "pkg:deb/ubuntu/curl@7.68.0-1ubuntu2.25+esm5?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "7.65.3-1ubuntu3",
        "7.65.3-1ubuntu4",
        "7.66.0-1ubuntu1",
        "7.67.0-2ubuntu1",
        "7.68.0-1ubuntu1",
        "7.68.0-1ubuntu2",
        "7.68.0-1ubuntu2.1",
        "7.68.0-1ubuntu2.2",
        "7.68.0-1ubuntu2.4",
        "7.68.0-1ubuntu2.5",
        "7.68.0-1ubuntu2.6",
        "7.68.0-1ubuntu2.7",
        "7.68.0-1ubuntu2.10",
        "7.68.0-1ubuntu2.11",
        "7.68.0-1ubuntu2.12",
        "7.68.0-1ubuntu2.13",
        "7.68.0-1ubuntu2.14",
        "7.68.0-1ubuntu2.15",
        "7.68.0-1ubuntu2.16",
        "7.68.0-1ubuntu2.18",
        "7.68.0-1ubuntu2.19",
        "7.68.0-1ubuntu2.20",
        "7.68.0-1ubuntu2.21",
        "7.68.0-1ubuntu2.22",
        "7.68.0-1ubuntu2.23",
        "7.68.0-1ubuntu2.24",
        "7.68.0-1ubuntu2.25",
        "7.68.0-1ubuntu2.25+esm2",
        "7.68.0-1ubuntu2.25+esm3",
        "7.68.0-1ubuntu2.25+esm4",
        "7.68.0-1ubuntu2.25+esm5"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "curl",
            "binary_version": "7.81.0-1ubuntu1.24"
          },
          {
            "binary_name": "libcurl3-gnutls",
            "binary_version": "7.81.0-1ubuntu1.24"
          },
          {
            "binary_name": "libcurl3-nss",
            "binary_version": "7.81.0-1ubuntu1.24"
          },
          {
            "binary_name": "libcurl4",
            "binary_version": "7.81.0-1ubuntu1.24"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "curl",
        "purl": "pkg:deb/ubuntu/curl@7.81.0-1ubuntu1.24?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.81.0-1ubuntu1.24"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "7.74.0-1.3ubuntu2",
        "7.74.0-1.3ubuntu3",
        "7.80.0-3",
        "7.81.0-1",
        "7.81.0-1ubuntu1.1",
        "7.81.0-1ubuntu1.2",
        "7.81.0-1ubuntu1.3",
        "7.81.0-1ubuntu1.4",
        "7.81.0-1ubuntu1.6",
        "7.81.0-1ubuntu1.7",
        "7.81.0-1ubuntu1.8",
        "7.81.0-1ubuntu1.10",
        "7.81.0-1ubuntu1.11",
        "7.81.0-1ubuntu1.13",
        "7.81.0-1ubuntu1.14",
        "7.81.0-1ubuntu1.15",
        "7.81.0-1ubuntu1.16",
        "7.81.0-1ubuntu1.17",
        "7.81.0-1ubuntu1.18",
        "7.81.0-1ubuntu1.19",
        "7.81.0-1ubuntu1.20",
        "7.81.0-1ubuntu1.21",
        "7.81.0-1ubuntu1.22",
        "7.81.0-1ubuntu1.23"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "curl",
            "binary_version": "8.5.0-2ubuntu10.9"
          },
          {
            "binary_name": "libcurl3t64-gnutls",
            "binary_version": "8.5.0-2ubuntu10.9"
          },
          {
            "binary_name": "libcurl4t64",
            "binary_version": "8.5.0-2ubuntu10.9"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "curl",
        "purl": "pkg:deb/ubuntu/curl@8.5.0-2ubuntu10.9?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.5.0-2ubuntu10.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.2.1-1ubuntu3",
        "8.2.1-1ubuntu3.1",
        "8.4.0-2ubuntu1",
        "8.5.0-2ubuntu1",
        "8.5.0-2ubuntu2",
        "8.5.0-2ubuntu8",
        "8.5.0-2ubuntu9",
        "8.5.0-2ubuntu10",
        "8.5.0-2ubuntu10.1",
        "8.5.0-2ubuntu10.2",
        "8.5.0-2ubuntu10.3",
        "8.5.0-2ubuntu10.4",
        "8.5.0-2ubuntu10.5",
        "8.5.0-2ubuntu10.6",
        "8.5.0-2ubuntu10.7",
        "8.5.0-2ubuntu10.8"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "curl",
            "binary_version": "8.14.1-2ubuntu1.3"
          },
          {
            "binary_name": "libcurl3t64-gnutls",
            "binary_version": "8.14.1-2ubuntu1.3"
          },
          {
            "binary_name": "libcurl4t64",
            "binary_version": "8.14.1-2ubuntu1.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "curl",
        "purl": "pkg:deb/ubuntu/curl@8.14.1-2ubuntu1.3?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.14.1-2ubuntu1.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.12.1-3ubuntu1",
        "8.13.0-5ubuntu1",
        "8.14.1-1ubuntu2",
        "8.14.1-1ubuntu3",
        "8.14.1-2ubuntu1",
        "8.14.1-2ubuntu1.1",
        "8.14.1-2ubuntu1.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "curl",
            "binary_version": "8.18.0-1ubuntu2.1"
          },
          {
            "binary_name": "libcurl3t64-gnutls",
            "binary_version": "8.18.0-1ubuntu2.1"
          },
          {
            "binary_name": "libcurl4t64",
            "binary_version": "8.18.0-1ubuntu2.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "curl",
        "purl": "pkg:deb/ubuntu/curl@8.18.0-1ubuntu2.1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.18.0-1ubuntu2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.14.1-2ubuntu1",
        "8.17.0-1ubuntu1",
        "8.18.0-1ubuntu1",
        "8.18.0-1ubuntu2"
      ]
    }
  ],
  "aliases": [],
  "details": "curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1. curl is setup to use specific different proxies for different URL schemes 2. the first proxy needs credentials 3. the second proxy uses no credentials 4. while using the first proxy (using say `http://`), curl is asked to follow    a redirect to a URL using another scheme (say `https://`), accessed using a    second, different, proxy",
  "id": "UBUNTU-CVE-2026-6253",
  "modified": "2026-07-10T00:02:01Z",
  "published": "2026-04-29T14:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-6253"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-6253"
    },
    {
      "type": "REPORT",
      "url": "https://curl.se/docs/CVE-2026-6253.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8227-1"
    }
  ],
  "related": [
    "USN-8227-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-6253"
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.