USN-8989-1 (UBUNTU-CVE-2026-26961)

Vulnerability from osv_ubuntu – Published: 2026-11-03 17:12 – Updated: 2026-11-03 17:12 – Source website
VLAI
Summary
ruby-rack vulnerabilities
Details

Andrew Lacambra discovered that Rack did not properly parse certain regular expressions. An attacker could possibly use this issue to bypass network security filters. (CVE-2026-26961)

William T. Nelson discovered that Rack did not handle multipart headers correctly. An attacker could possibly use this issue to cause downstream parsing issues or a denial of service. (CVE-2026-26962)

It was discovered that Rack did not handle the Forwarded header correctly. An attacker could possibly use this issue to manipulate header values. (CVE-2026-32762)

It was discovered that Rack could consume excessive CPU when handling certain Accept-Encoding values. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-34230)

Haruki Oyama discovered that certain configurations of Rack could erroneously fail to derive the displayed directory path, and expose the full file system path. An attacker could possibly use this issue to disclose deployment details such as layout and usernames. (CVE-2026-34763)

It was discovered that Rack did not properly handle static file paths. An attacker could possibly use this issue to exfiltrate unintentionally served data. (CVE-2026-34785)

Haruki Oyama discovered that Rack did not apply header rules to certain requests for URL-encoded static paths. An attacker could possibly use this issue to bypass security-relevant response headers. (CVE-2026-34786)

It was discovered that Rack did not limit the number of ranges requested in the Range header. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-34826)

It was discovered that Rack could consume excessive CPU when parsing certain multipart parameters. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-34827)

It was discovered that Rack could consume unbounded disk space when handling requests without a Content-Length header. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-34829)

Mehtab Zafar discovered that Rack directly interpreted the X-Accel-Mapping header as a regular expression without escaping. An attacker could possibly use this issue to exfiltrate arbitrary files from internal locations. (CVE-2026-34830)

It was discovered that Rack did not properly handle messages with Unicode. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-34831)

It was discovered that Rack did not properly parse the Host header. An attacker could possibly use this issue to bypass security filters or poison generated links. (CVE-2026-34835)

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-26961",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-26962",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-32762",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-34230",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-34763",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-34785",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-34786",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-34826",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-34827",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-34829",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-34830",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-34831",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-34835",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:26.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "ruby-rack",
            "binary_version": "3.2.4-1ubuntu1.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "ruby-rack",
        "purl": "pkg:deb/ubuntu/ruby-rack@3.2.4-1ubuntu1.1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.2.4-1ubuntu1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.1.16-0.1",
        "3.1.18-1",
        "3.1.18-1build1",
        "3.2.4-1ubuntu1"
      ]
    }
  ],
  "aliases": [],
  "details": "Andrew Lacambra discovered that Rack did not properly parse certain regular\nexpressions. An attacker could possibly use this issue to bypass network\nsecurity filters. (CVE-2026-26961)\n\nWilliam T. Nelson discovered that Rack did not handle multipart headers\ncorrectly. An attacker could possibly use this issue to cause downstream\nparsing issues or a denial of service. (CVE-2026-26962)\n\nIt was discovered that Rack did not handle the Forwarded header correctly.\nAn attacker could possibly use this issue to manipulate header values.\n(CVE-2026-32762)\n\nIt was discovered that Rack could consume excessive CPU when handling\ncertain Accept-Encoding values. An attacker could possibly use this issue\nto cause a denial of service. (CVE-2026-34230)\n\nHaruki Oyama discovered that certain configurations of Rack could\nerroneously fail to derive the displayed directory path, and expose the\nfull file system path. An attacker could possibly use this issue to\ndisclose deployment details such as layout and usernames. (CVE-2026-34763)\n\nIt was discovered that Rack did not properly handle static file paths. An\nattacker could possibly use this issue to exfiltrate unintentionally served\ndata. (CVE-2026-34785)\n\nHaruki Oyama discovered that Rack did not apply header rules to certain\nrequests for URL-encoded static paths. An attacker could possibly use this\nissue to bypass security-relevant response headers. (CVE-2026-34786)\n\nIt was discovered that Rack did not limit the number of ranges requested in\nthe Range header. An attacker could possibly use this issue to cause a\ndenial of service. (CVE-2026-34826)\n\nIt was discovered that Rack could consume excessive CPU when parsing\ncertain multipart parameters. An attacker could possibly use this issue to\ncause a denial of service. (CVE-2026-34827)\n\nIt was discovered that Rack could consume unbounded disk space when\nhandling requests without a Content-Length header. An attacker could\npossibly use this issue to cause a denial of service. (CVE-2026-34829)\n\nMehtab Zafar discovered that Rack directly interpreted the X-Accel-Mapping\nheader as a regular expression without escaping. An attacker could possibly\nuse this issue to exfiltrate arbitrary files from internal locations.\n(CVE-2026-34830)\n\nIt was discovered that Rack did not properly handle messages with Unicode.\nAn attacker could possibly use this issue to cause a denial of service.\n(CVE-2026-34831)\n\nIt was discovered that Rack did not properly parse the Host header. An\nattacker could possibly use this issue to bypass security filters or poison\ngenerated links. (CVE-2026-34835)",
  "id": "USN-8989-1",
  "modified": "2026-11-03T17:12:03Z",
  "published": "2026-11-03T17:12:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8989-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-26961"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-26962"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-32762"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34230"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34763"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34785"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34786"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34826"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34827"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34829"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34830"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34831"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34835"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "ruby-rack vulnerabilities",
  "upstream": [
    "UBUNTU-CVE-2026-26961",
    "UBUNTU-CVE-2026-26962",
    "UBUNTU-CVE-2026-32762",
    "UBUNTU-CVE-2026-34230",
    "UBUNTU-CVE-2026-34763",
    "UBUNTU-CVE-2026-34785",
    "UBUNTU-CVE-2026-34786",
    "UBUNTU-CVE-2026-34826",
    "UBUNTU-CVE-2026-34827",
    "UBUNTU-CVE-2026-34829",
    "UBUNTU-CVE-2026-34830",
    "UBUNTU-CVE-2026-34831",
    "UBUNTU-CVE-2026-34835"
  ]
}



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