MediumFix available

erlang-jose RSA JWK parsing attempts to factor an attacker-controlled modulus, enabling CPU-exhaustion denial of service

Type: advisorySources: OSV

## Summary 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.

Products: jose
Affected versions: 1.10.0, 1.10.1, 1.11.0, 1.11.1, 1.11.10, 1.11.11, 1.11.12, 1.11.2, 1.11.4, 1.11.5, 1.11.6, 1.11.7, 1.11.8, 1.11.9, 1.7.7, 1.7.8, 1.7.9, 1.8.0, 1.8.1, 1.8.2, 1.8.3, 1.8.4, 1.9.0
Fixed versions: 1.11.13
CVEs: CVE-2026-65631
Confirmed fixed CVEs: Not specified
Updated in this feed: 1 Nov 2026, 16:51 UTC · Revision 1

Source evidence

erlang-jose RSA JWK parsing attempts to factor an attacker-controlled modulus, enabling CPU-exhaustion denial of service

core-osv · Original source

Published 26 Oct 2026, 19:53 UTC

osv:EEF-CVE-2026-65631

jose

Fixed versions: 1.11.13

Complete source record

{
  "id": "db4f38782d00deeb7dee9593bf5bce741705881335e110487dc290f7e4a997b3",
  "url": "https://osv.dev/vulnerability/EEF-CVE-2026-65631",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "erlang-jose RSA JWK parsing attempts to factor an attacker-controlled modulus, enabling CPU-exhaustion denial of service",
    "summary": "## Summary 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.",
    "evidence": "osv:EEF-CVE-2026-65631",
    "products": [
      {
        "name": {
          "value": "jose",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.11.13",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.10.0",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.10.1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.11.0",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.11.1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.11.10",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.11.11",
            "evidence": "/affected/0/versions"
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          {
            "value": "1.11.12",
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            "value": "1.11.2",
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          {
            "value": "1.11.4",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.11.5",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.11.6",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.11.7",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.11.8",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.11.9",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.7.7",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.7.8",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.7.9",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.8.0",
            "evidence": "/affected/0/versions"
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          {
            "value": "1.8.1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.8.2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.8.3",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.8.4",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.9.0",
            "evidence": "/affected/0/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "EEF-CVE-2026-65631",
      "aliases": [
        "CVE-2026-65631",
        "EEF-CVE-2026-65631",
        "GHSA-3m45-vrpj-xmrq"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "1.7.7"
                },
                {
                  "fixed": "1.11.13"
                }
              ]
            }
          ],
          "package": {
            "name": "jose",
            "purl": "pkg:hex/jose",
            "ecosystem": "Hex"
          },
          "versions": [
            "1.10.0",
            "1.10.1",
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            "1.11.1",
            "1.11.10",
            "1.11.11",
            "1.11.12",
            "1.11.2",
            "1.11.4",
            "1.11.5",
            "1.11.6",
            "1.11.7",
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            "1.8.0",
            "1.8.1",
            "1.8.2",
            "1.8.3",
            "1.8.4",
            "1.9.0"
          ],
          "database_specific": {
            "source": "https://cna.erlef.org/osv/EEF-CVE-2026-65631.json"
          }
        },
        {
          "ranges": [
            {
              "repo": "https://github.com/potatosalad/erlang-jose",
              "type": "GIT",
              "events": [
                {
                  "introduced": "d19e1ba68d88c68d29aa942be2573a22dbafca1f"
                },
                {
                  "fixed": "bfd336c0062bff93e65d08c22361897e96afd956"
                }
              ]
            }
          ],
          "versions": [
            "1.11.12",
            "1.11.11",
            "1.11.10",
            "1.11.9",
            "1.11.8",
            "1.11.7",
            "1.11.5",
            "1.11.4",
            "1.11.2",
            "1.11.1",
            "1.11.0",
            "1.10.1",
            "1.10.0",
            "1.9.0",
            "1.8.4",
            "1.8.3",
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            "1.8.1",
            "1.8.0",
            "1.7.9",
            "1.7.8",
            "1.7.7"
          ],
          "database_specific": {
            "source": "https://cna.erlef.org/osv/EEF-CVE-2026-65631.json"
          }
        }
      ],
      "modified": "2026-10-26T20:11:07.682468010Z",
      "provider": "osv",
      "references": [
        "https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-3m45-vrpj-xmrq",
        "https://cna.erlef.org/cves/CVE-2026-65631.html",
        "https://github.com/potatosalad/erlang-jose/commit/d19e1ba68d88c68d29aa942be2573a22dbafca1f",
        "https://github.com/potatosalad/erlang-jose/commit/bfd336c0062bff93e65d08c22361897e96afd956",
        "https://hex.pm/packages/jose"
      ],
      "provider_metadata": {
        "cpe_ids": [
          "cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:*"
        ],
        "cwe_ids": [
          "CWE-407"
        ],
        "capec_ids": [
          "CAPEC-130"
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-65631",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 458967,
  "published_at": "2026-10-26T19:53:45.204+00:00"
}