{"id":"EEF-CVE-2026-65631","aliases":["CVE-2026-65631","GHSA-3m45-vrpj-xmrq"],"title":"erlang-jose RSA JWK parsing attempts to factor an attacker-controlled modulus, enabling CPU-exhaustion denial of service","titleSource":"OSV","descriptionSource":"OSV","description":"## Summary\n\nInefficient 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.\n\nWhen 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.\n\nThis issue affects jose: from 1.7.7 before 1.11.13.","severity":"medium","score":6.9,"published":"2026-10-26T19:53:45.204Z","modified":"2026-10-26T20:11:07.682Z","withdrawn":false,"knownExploited":false,"affected":[{"ecosystem":"Hex","name":"jose","sources":[{"name":"OSV · EEF-CVE-2026-65631","url":"https://osv.dev/vulnerability/EEF-CVE-2026-65631"}],"ranges":[{"events":[{"introduced":"1.7.7"},{"fixed":"1.11.13"}],"type":"SEMVER"}],"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":["1.11.13"]}],"sourceAffected":[{"ranges":[{"events":[{"introduced":"d19e1ba68d88c68d29aa942be2573a22dbafca1f"},{"fixed":"bfd336c0062bff93e65d08c22361897e96afd956"}],"type":"GIT","repo":"https://github.com/potatosalad/erlang-jose"}],"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","1.8.2","1.8.1","1.8.0","1.7.9","1.7.8","1.7.7"]}],"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","https://osv.dev/vulnerability/EEF-CVE-2026-65631"],"sources":[{"name":"OSV","id":"EEF-CVE-2026-65631","modified":"2026-10-26T20:11:07.682468010Z","url":"https://osv.dev/vulnerability/EEF-CVE-2026-65631"},{"name":"CVE","id":"CVE-2026-65631","modified":"2026-10-26T19:53:45.204Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-65631"}],"assessments":[{"source":"OSV","vector":"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","score":6.9},{"source":"EEF","vector":"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","score":6.9}],"products":[{"vendor":"potatosalad","name":"jose","platforms":[],"versions":[{"version":"1.7.7","status":"affected","lessThan":"1.11.13","versionType":"semver"}],"defaultStatus":"unaffected","source":"EEF","url":"https://www.cve.org/CVERecord?id=CVE-2026-65631"},{"vendor":"potatosalad","name":"jose","platforms":[],"versions":[{"version":"d19e1ba68d88c68d29aa942be2573a22dbafca1f","status":"affected","lessThan":"bfd336c0062bff93e65d08c22361897e96afd956","versionType":"git"}],"defaultStatus":"unaffected","source":"EEF","url":"https://www.cve.org/CVERecord?id=CVE-2026-65631"}],"remediation":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T20:50:31.340Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}