ubuntu-cve-2026-33996
Vulnerability from osv_ubuntu
Published
2026-03-27 23:17
Modified
2026-05-20 15:27
Summary
Details

LibJWT is a C JSON Web Token Library. Starting in version 3.0.0 and prior to version 3.3.0, the JWK parsing for RSA-PSS did not protect against a NULL value when expecting to parse JSON string values. A specially crafted JWK file could exploit this behavior by using integers in places where the code expected a string. This was fixed in v3.3.0. A workaround is available. Users importing keys through a JWK file should not do so from untrusted sources. Use the jwk2key tool to check for validity of a JWK file. Likewise, if possible, do not use JWK files with RSA-PSS keys.

Severity
5.8 (Medium)
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:A/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjwt0",
            "binary_version": "1.9.0-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "libjwt",
        "purl": "pkg:deb/ubuntu/libjwt@1.9.0-1build1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.8.0+dfsg-1",
        "1.8.0+dfsg-2",
        "1.9.0-1",
        "1.9.0-1build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjwt-gnutls0",
            "binary_version": "1.10.2-1"
          },
          {
            "binary_name": "libjwt0",
            "binary_version": "1.10.2-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "libjwt",
        "purl": "pkg:deb/ubuntu/libjwt@1.10.2-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.10.2-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjwt-gnutls0",
            "binary_version": "1.10.2-1build1"
          },
          {
            "binary_name": "libjwt0",
            "binary_version": "1.10.2-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "libjwt",
        "purl": "pkg:deb/ubuntu/libjwt@1.10.2-1build1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.10.2-1",
        "1.10.2-1build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjwt-gnutls2",
            "binary_version": "1.17.0-2build2"
          },
          {
            "binary_name": "libjwt2",
            "binary_version": "1.17.0-2build2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libjwt",
        "purl": "pkg:deb/ubuntu/libjwt@1.17.0-2build2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.10.2-1build1",
        "1.17.0-2",
        "1.17.0-2build1",
        "1.17.0-2build2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjwt-gnutls2",
            "binary_version": "1.17.2-1"
          },
          {
            "binary_name": "libjwt2",
            "binary_version": "1.17.2-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "libjwt",
        "purl": "pkg:deb/ubuntu/libjwt@1.17.2-1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.17.2-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libjwt-gnutls2",
            "binary_version": "1.17.2-1build1"
          },
          {
            "binary_name": "libjwt2",
            "binary_version": "1.17.2-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libjwt",
        "purl": "pkg:deb/ubuntu/libjwt@1.17.2-1build1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.17.2-1",
        "1.17.2-1build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jwt-tools",
            "binary_version": "3.2.3-1"
          },
          {
            "binary_name": "libjwt14",
            "binary_version": "3.2.3-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libjwt3",
        "purl": "pkg:deb/ubuntu/libjwt3@3.2.3-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.2.2-1",
        "3.2.3-1"
      ]
    }
  ],
  "aliases": [],
  "details": "LibJWT is a C JSON Web Token Library. Starting in version 3.0.0 and prior to version 3.3.0, the JWK parsing for RSA-PSS did not protect against a NULL value when expecting to parse JSON string values. A specially crafted JWK file could exploit this behavior by using integers in places where the code expected a string. This was fixed in v3.3.0. A workaround is available. Users importing keys through a JWK file should not do so from untrusted sources. Use the `jwk2key` tool to check for validity of a JWK file. Likewise, if possible, do not use JWK files with RSA-PSS keys.",
  "id": "UBUNTU-CVE-2026-33996",
  "modified": "2026-05-20T15:27:23Z",
  "published": "2026-03-27T23:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-33996"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-33996"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/benmcollins/libjwt/security/advisories/GHSA-ph96-hqpc-9f66"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/benmcollins/libjwt/commit/cfd890286fa49ae61b534c937c9f0428b5c6034c"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:A/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-33996"
  ]
}



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