{"id":"CVE-2026-65631","title":"erlang-jose RSA JWK parsing attempts to factor an attacker-controlled modulus, enabling CPU-exhaustion denial of service","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.\n\nWhen an application parses an untrusted JWK through the pu…","severity":"medium","cvss":6.9,"cvssVector":"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","cvssSource":"cna","cwe":["CWE-407"],"vendor":"potatosalad","product":"jose","affected":["jose >= 1.7.7 < 1.11.13","potatosalad/erlang-jose >= d19e1ba68d88c68d29aa942be2573a22dbafca1f < bfd336c0062bff93e65d08c22361897e96afd956"],"published":"2026-10-26","updated":"2026-10-26","sourceUpdated":"2026-10-26T19:53:45.204Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-65631","references":[{"url":"https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-3m45-vrpj-xmrq"},{"url":"https://cna.erlef.org/cves/CVE-2026-65631.html","label":"EEF CNA record for CVE-2026-65631"},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-65631","label":"OSV record EEF-CVE-2026-65631"},{"url":"https://github.com/potatosalad/erlang-jose/commit/d19e1ba68d88c68d29aa942be2573a22dbafca1f","label":"Introducing commit d19e1ba in potatosalad/erlang-jose"},{"url":"https://github.com/potatosalad/erlang-jose/commit/bfd336c0062bff93e65d08c22361897e96afd956","label":"Fix commit bfd336c in potatosalad/erlang-jose"}],"tags":["cve.org"],"ingestedAt":"2026-10-26T20:39:42.625Z","epss":0.00235,"epssPercentile":0.14301,"slug":"CVE-2026-65631","body":"## Overview\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.\n\n## Affected\n\n- `jose >= 1.7.7 < 1.11.13`\n- `potatosalad/erlang-jose >= d19e1ba68d88c68d29aa942be2573a22dbafca1f < bfd336c0062bff93e65d08c22361897e96afd956`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":38,"depthScoreParts":{"impact":38,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}