CVE catalog

CVE-2026-26962

Rack is a modular Ruby web server interface. From…

Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an obs-fold sequence, Rack preserves the embedded CRLF in parsed parameter values such as filename or name instead of removing the folded line break during unfolding. As a result, applications that later reuse those parsed values in HTTP response headers may be vulnerable to downstream header injection or response splitting. This issue has been patched in version 3.2.6.

Severity: Medium · CVSS 4.8CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Published: Apr 2, 2026, 5:10:17 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.23% · Oct 27, 2026

Projects and upstream resources

[ruby-rack][Source-reported homepage]

Reported versions and fixes

Each observation applies to its named package, distribution, and release. Distribution backports can fix a vulnerability while retaining an older upstream version number.

Version impact has not been established. The original provider fields are retained below.

Provider details and historical evidence

Original provider fields

{
  "package_releases": [
    {
      "name": "ruby-rack",
      "status": "fixed",
      "release": "sid",
      "version": "3.2.7-1"
    },
    {
      "name": "ruby-rack",
      "status": "fixed",
      "release": "forky",
      "version": "3.2.7-1"
    },
    {
      "name": "ruby-rack",
      "status": "vulnerable",
      "release": "trixie",
      "version": "3.1.20-0+deb13u1"
    },
    {
      "name": "ruby-rack",
      "status": "fixed",
      "release": "trixie-security",
      "version": "3.1.20-0+deb13u2"
    },
    {
      "name": "ruby-rack",
      "status": "not affected",
      "release": "bookworm",
      "version": "2.2.22-0+deb12u1"
    },
    {
      "name": "ruby-rack",
      "status": "not affected",
      "release": "bookworm-security",
      "version": "2.2.22-0+deb12u2"
    }
  ],
  "fixed_versions": [
    {
      "bug": null,
      "name": "ruby-rack",
      "type": "source",
      "origin": null,
      "release": "sid",
      "urgency": "not yet assigned",
      "fixed_version": "3.2.6-2"
    },
    {
      "bug": null,
      "name": "ruby-rack",
      "type": "source",
      "origin": null,
      "release": "forky",
      "urgency": "not yet assigned",
      "fixed_version": "3.2.6-2"
    },
    {
      "bug": null,
      "name": "ruby-rack",
      "type": "source",
      "origin": null,
      "release": "trixie",
      "urgency": "not yet assigned",
      "fixed_version": "3.1.20-0+deb13u2"
    },
    {
      "bug": null,
      "name": "ruby-rack",
      "type": "source",
      "origin": null,
      "release": "bookworm",
      "urgency": "unimportant",
      "fixed_version": "0"
    }
  ],
  "distribution_packages": [
    {
      "name": "ruby-rack",
      "ecosystem": "cpe",
      "fixed_version": "2.2.7-1ubuntu0.7"
    },
    {
      "name": "ruby-rack",
      "ecosystem": "cpe",
      "fixed_version": "not yet fixed"
    },
    {
      "name": "rack",
      "ecosystem": "cpe",
      "fixed_version": "3.2.6"
    },
    {
      "name": "ruby-rack",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            }
          ]
        }
      ],
      "release": "pro",
      "versions": [
        "2.0.6-3",
        "2.0.7-2",
        "2.0.7-2ubuntu0.1",
        "2.0.7-2ubuntu0.1+esm1",
        "2.0.7-2ubuntu0.1+esm2",
        "2.0.7-2ubuntu0.1+esm3",
        "2.0.7-2ubuntu0.1+esm4",
        "2.0.7-2ubuntu0.1+esm5",
        "2.0.7-2ubuntu0.1+esm6",
        "2.0.7-2ubuntu0.1+esm7",
        "2.0.7-2ubuntu0.1+esm8",
        "2.0.7-2ubuntu0.1+esm9",
        "2.0.7-2ubuntu0.1+esm10"
      ],
      "ecosystem": "deb",
      "fixed_version": "",
      "provider_record_id": "UBUNTU-CVE-2026-26962"
    },
    {
      "name": "ruby-rack",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            }
          ]
        }
      ],
      "release": "22.04",
      "versions": [
        "2.1.4-3",
        "2.1.4-4",
        "2.1.4-5",
        "2.1.4-5ubuntu1",
        "2.1.4-5ubuntu1.1",
        "2.1.4-5ubuntu1.2"
      ],
      "ecosystem": "deb",
      "fixed_version": "",
      "provider_record_id": "UBUNTU-CVE-2026-26962"
    },
    {
      "name": "ruby-rack",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.2.7-1ubuntu0.7"
            }
          ]
        }
      ],
      "release": "24.04",
      "versions": [
        "2.2.4-3",
        "2.2.7-1",
        "2.2.7-1ubuntu0.1",
        "2.2.7-1ubuntu0.2",
        "2.2.7-1ubuntu0.3",
        "2.2.7-1ubuntu0.4",
        "2.2.7-1ubuntu0.5",
        "2.2.7-1ubuntu0.6"
      ],
      "ecosystem": "deb",
      "fixed_version": "2.2.7-1ubuntu0.7",
      "provider_record_id": "UBUNTU-CVE-2026-26962"
    },
    {
      "name": "ruby-rack",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.16-0.1ubuntu0.3"
            }
          ]
        }
      ],
      "release": "25.10",
      "versions": [
        "2.2.7-1.1",
        "3.1.16-0.1",
        "3.1.16-0.1ubuntu0.1",
        "3.1.16-0.1ubuntu0.2"
      ],
      "ecosystem": "deb",
      "fixed_version": "3.1.16-0.1ubuntu0.3",
      "provider_record_id": "UBUNTU-CVE-2026-26962"
    },
    {
      "name": "ruby-rack",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            }
          ]
        }
      ],
      "release": "26.04",
      "versions": [
        "3.1.16-0.1",
        "3.1.18-1",
        "3.1.18-1build1",
        "3.2.4-1ubuntu1"
      ],
      "ecosystem": "deb",
      "fixed_version": "",
      "provider_record_id": "UBUNTU-CVE-2026-26962"
    }
  ]
}

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

[ruby-rack]Unknown
Details (4)
- 2.2.22-0+deb12u1 · all · bookworm
  Not affected
  nvd · ruby-rack · debian · bookworm
- 2.2.22-0+deb12u1 · all · bookworm
  Not affected
  nvd · ruby-rack · debian · bookworm
- 2.2.22-0+deb12u2 · all · bookworm-security
  Not affected
  nvd · ruby-rack · debian · bookworm
- 2.2.22-0+deb12u2 · all · bookworm-security
  Not affected
  nvd · ruby-rack · debian · bookworm

[Debian 13 (Trixie)]

[ruby-rack]Unknown
Details (5)
- 3.1.20-0+deb13u1 · all · trixie
  Affected · Fixed: 3.1.20-0+deb13u2
  nvd · ruby-rack · debian · 13
- 3.1.20-0+deb13u1 · all · trixie
  Affected · Fixed: 3.1.20-0+deb13u2
  nvd · ruby-rack · debian · 13
- 3.1.20-0+deb13u1 · all · trixie-security
  Affected · Fixed: 3.1.20-0+deb13u2
  nvd · ruby-rack · debian · 13
- 3.1.20-0+deb13u1 · all · trixie-security · Historical version
  Affected · Fixed: 3.1.20-0+deb13u2
  nvd · ruby-rack · debian · 13
- 3.1.20-0+deb13u2 · all · trixie-security
  Fixed · Fixed: 3.1.20-0+deb13u2
  nvd · ruby-rack · debian · 13

Observed: Oct 27, 2026, 8:00:35 AM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]