UBUNTU-CVE-2026-65631 (CVE-2026-65631)

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

Inefficient Algorithmic Complexity in erlang-jose allows an unauthenticated remote attacker to cause a CPU-exhaustion denial of service by submitting a crafted RSA JSON Web Key. When an application parses an untrusted JWK through the public jose_jwk:from_binary/1 or jose_jwk:from_map/1 API (or the Elixir wrappers JOSE.JWK.from_binary/1 and JOSE.JWK.from_map/1), an RSA private key that supplies d, e, and n but omits all Chinese Remainder Theorem parameters (p, q, dp, dq, qi) is routed into convert_sfm_to_crt/1, which tries to recover the missing primes by factoring the modulus. The three integers are read straight from the base64url input and are never validated as a real RSA key. When the modulus cannot be split into two factors (for example, when it is itself prime), the search loop convert_sfm_to_crt_find_p/6 performs a modular exponentiation over the attacker-sized modulus on every iteration and never succeeds. A single request of a few hundred bytes forces close to one CPU-second of work before an internal one-second watchdog kills the worker, and a larger modulus raises the cost further. By flooding such requests an attacker can saturate every scheduler and deny service, without credentials, a valid RSA key, or any special configuration. This issue affects jose: from 1.7.7 before 1.11.13.

Severity
6.9 (Medium)
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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": "Inefficient Algorithmic Complexity in erlang-jose allows an unauthenticated remote attacker to cause a CPU-exhaustion denial of service by submitting a crafted RSA JSON Web Key. When an application parses an untrusted JWK through the public jose_jwk:from_binary/1 or jose_jwk:from_map/1 API (or the Elixir wrappers JOSE.JWK.from_binary/1 and JOSE.JWK.from_map/1), an RSA private key that supplies d, e, and n but omits all Chinese Remainder Theorem parameters (p, q, dp, dq, qi) is routed into convert_sfm_to_crt/1, which tries to recover the missing primes by factoring the modulus. The three integers are read straight from the base64url input and are never validated as a real RSA key. When the modulus cannot be split into two factors (for example, when it is itself prime), the search loop convert_sfm_to_crt_find_p/6 performs a modular exponentiation over the attacker-sized modulus on every iteration and never succeeds. A single request of a few hundred bytes forces close to one CPU-second of work before an internal one-second watchdog kills the worker, and a larger modulus raises the cost further. By flooding such requests an attacker can saturate every scheduler and deny service, without credentials, a valid RSA key, or any special configuration. This issue affects jose: from 1.7.7 before 1.11.13.",
  "id": "UBUNTU-CVE-2026-65631",
  "modified": "2026-10-27T00:00:00Z",
  "published": "2026-10-27T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-65631"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-65631"
    },
    {
      "type": "REPORT",
      "url": "https://cna.erlef.org/cves/cve-2026-65631.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/bfd336c0062bff93e65d08c22361897e96afd956"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/potatosalad/erlang-jose/commit/d19e1ba68d88c68d29aa942be2573a22dbafca1f"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/potatosalad/erlang-jose/security/advisories/ghsa-3m45-vrpj-xmrq"
    },
    {
      "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-2026-65631.json"
    },
    {
      "type": "REPORT",
      "url": "https://nvd.nist.gov/vuln/detail/cve-2026-65631"
    },
    {
      "type": "REPORT",
      "url": "https://osv.dev/vulnerability/eef-cve-2026-65631"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-65631"
  ]
}



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