UBUNTU-CVE-2026-65625 (CVE-2026-65625)

Vulnerability from osv_ubuntu – Published: 2026-10-27 00:00 – Updated: 2026-10-27 00:00 – Source website
VLAI
Details

The pure-Erlang AES-GCM fallback in jose_jwa_aes derives the number of verified authentication tag bits from the attacker-supplied tag itself. In the {aes_gcm, Bits} clause of block_decrypt/4, the incoming tag is guarded only by is_binary/1, with no check on its length. Verification in gcm_block_decrypt/6 then computes TBits = bit_size(T) and compares only those bits of the real 128-bit tag. An attacker who controls a JWE token can truncate the authentication tag to as little as 8 bits, so only 8 bits are ever checked. This reduces forgery resistance from 2^-128 to 2^-8, and a forged ciphertext is reliably accepted as authentic within 256 attempts without knowledge of the key (an authentication tag forgery and integrity bypass). Supplying a tag longer than 128 bits instead causes a badmatch that crashes the decrypting process. The fallback is reached through the public JWE decryption path whenever AES-GCM is not provided by a native crypto NIF, for example on FIPS or stripped or older OTP builds. This issue affects jose: from 1.2.0 before 1.11.13.

Severity
5.9 (Medium)
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jose",
            "binary_version": "10-2build1"
          },
          {
            "binary_name": "libjose0",
            "binary_version": "10-2build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "jose",
        "purl": "pkg:deb/ubuntu/jose@10-2build1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "10-2",
        "10-2build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jose",
            "binary_version": "10-2build2"
          },
          {
            "binary_name": "libjose0",
            "binary_version": "10-2build2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "jose",
        "purl": "pkg:deb/ubuntu/jose@10-2build2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "10-2build2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jose",
            "binary_version": "11-2"
          },
          {
            "binary_name": "libjose0",
            "binary_version": "11-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "jose",
        "purl": "pkg:deb/ubuntu/jose@11-2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "10-3",
        "11-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jose",
            "binary_version": "13-1"
          },
          {
            "binary_name": "libjose0",
            "binary_version": "13-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "jose",
        "purl": "pkg:deb/ubuntu/jose@13-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "11-2",
        "11-3",
        "11-3build1",
        "11-3build2",
        "13-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jose",
            "binary_version": "14-2build2"
          },
          {
            "binary_name": "libjose0",
            "binary_version": "14-2build2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.10",
        "name": "jose",
        "purl": "pkg:deb/ubuntu/jose@14-2build2?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "14-2build1",
        "14-2build2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "jose",
            "binary_version": "14-2build1"
          },
          {
            "binary_name": "libjose0",
            "binary_version": "14-2build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "jose",
        "purl": "pkg:deb/ubuntu/jose@14-2build1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "14-2build1"
      ]
    }
  ],
  "aliases": [],
  "details": "The pure-Erlang AES-GCM fallback in jose_jwa_aes derives the number of verified authentication tag bits from the attacker-supplied tag itself. In the {aes_gcm, Bits} clause of block_decrypt/4, the incoming tag is guarded only by is_binary/1, with no check on its length. Verification in gcm_block_decrypt/6 then computes TBits = bit_size(T) and compares only those bits of the real 128-bit tag. An attacker who controls a JWE token can truncate the authentication tag to as little as 8 bits, so only 8 bits are ever checked. This reduces forgery resistance from 2^-128 to 2^-8, and a forged ciphertext is reliably accepted as authentic within 256 attempts without knowledge of the key (an authentication tag forgery and integrity bypass). Supplying a tag longer than 128 bits instead causes a badmatch that crashes the decrypting process. The fallback is reached through the public JWE decryption path whenever AES-GCM is not provided by a native crypto NIF, for example on FIPS or stripped or older OTP builds. This issue affects jose: from 1.2.0 before 1.11.13.",
  "id": "UBUNTU-CVE-2026-65625",
  "modified": "2026-10-27T00:00:00Z",
  "published": "2026-10-27T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-65625"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-65625"
    },
    {
      "type": "REPORT",
      "url": "https://cna.erlef.org/cves/cve-2026-65625.html"
    },
    {
      "type": "REPORT",
      "url": "https://github.com"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/potatosalad/erlang-jose"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/potatosalad/erlang-jose/commit/3fa1f8e3efda0da5ce6f4c9984789f979dc02740"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/potatosalad/erlang-jose/commit/8848b172575fb7d7e1e2977e8ae0a21678d2157a"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/potatosalad/erlang-jose/security/advisories/ghsa-6gxw-6f7r-cjr6"
    },
    {
      "type": "REPORT",
      "url": "https://hex.pm/packages/jose"
    },
    {
      "type": "REPORT",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/cveproject/cvelistv5/tree/main/cves/2026/65xxx/cve-2026-65625.json"
    },
    {
      "type": "REPORT",
      "url": "https://nvd.nist.gov/vuln/detail/cve-2026-65625"
    },
    {
      "type": "REPORT",
      "url": "https://osv.dev/vulnerability/eef-cve-2026-65625"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-65625"
  ]
}



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