{"id":"CVE-2026-65631","state":"PUBLISHED","title":"erlang-jose RSA JWK parsing attempts to factor an attacker-controlled modulus, enabling CPU-exhaustion denial of service","description":"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 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.","publishedAt":"2026-10-26T19:53:45.204Z","updatedAt":"2026-10-26T19:53:45.204Z","severity":{"score":6.9,"label":"Medium","version":"4.0","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","source":"EEF"},"assigner":"EEF","products":["potatosalad jose"],"affected":[{"vendor":"potatosalad","product":"jose","packageName":"jose","packageURL":"pkg:hex/jose","defaultStatus":"unaffected","versions":[{"version":"1.7.7","status":"affected","lessThan":"1.11.13","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:*"],"modules":["jose_jwk_kty_rsa","jose_jwk","'Elixir.JOSE.JWK'"],"programFiles":["src/jwk/jose_jwk_kty_rsa.erl","src/jwk/jose_jwk.erl","lib/jose/jwk.ex"],"programRoutines":[{"name":"jose_jwk_kty_rsa:from_map/1"},{"name":"jose_jwk_kty_rsa:convert_sfm_to_crt/1"},{"name":"jose_jwk_kty_rsa:convert_sfm_to_crt_find_p/6"},{"name":"jose_jwk:from_binary/1"},{"name":"jose_jwk:from_map/1"},{"name":"'Elixir.JOSE.JWK':from_binary/1"},{"name":"'Elixir.JOSE.JWK':from_map/1"}],"repo":"https://github.com/potatosalad/erlang-jose"},{"vendor":"potatosalad","product":"jose","packageName":"potatosalad/erlang-jose","packageURL":"pkg:github/potatosalad/erlang-jose","defaultStatus":"unaffected","versions":[{"version":"d19e1ba68d88c68d29aa942be2573a22dbafca1f","status":"affected","lessThan":"bfd336c0062bff93e65d08c22361897e96afd956","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:*"],"modules":["jose_jwk_kty_rsa","jose_jwk","'Elixir.JOSE.JWK'"],"programFiles":["src/jwk/jose_jwk_kty_rsa.erl","src/jwk/jose_jwk.erl","lib/jose/jwk.ex"],"programRoutines":[{"name":"jose_jwk_kty_rsa:from_map/1"},{"name":"jose_jwk_kty_rsa:convert_sfm_to_crt/1"},{"name":"jose_jwk_kty_rsa:convert_sfm_to_crt_find_p/6"},{"name":"jose_jwk:from_binary/1"},{"name":"jose_jwk:from_map/1"},{"name":"'Elixir.JOSE.JWK':from_binary/1"},{"name":"'Elixir.JOSE.JWK':from_map/1"}],"repo":"https://github.com/potatosalad/erlang-jose"}],"references":["https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-3m45-vrpj-xmrq","https://cna.erlef.org/cves/CVE-2026-65631.html","https://osv.dev/vulnerability/EEF-CVE-2026-65631","https://github.com/potatosalad/erlang-jose/commit/d19e1ba68d88c68d29aa942be2573a22dbafca1f","https://github.com/potatosalad/erlang-jose/commit/bfd336c0062bff93e65d08c22361897e96afd956"],"weaknesses":["CWE-407"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/65xxx/CVE-2026-65631.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-65631","state":"PUBLISHED","datePublished":"2026-10-26T19:53:45.204Z","dateUpdated":"2026-10-26T19:53:45.204Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-07-22T13:58:26.233Z"},"containers":{"cna":{"title":"erlang-jose RSA JWK parsing attempts to factor an attacker-controlled modulus, enabling CPU-exhaustion denial of service","descriptions":[{"lang":"en","value":"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 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."}],"affected":[{"vendor":"potatosalad","product":"jose","packageName":"jose","packageURL":"pkg:hex/jose","defaultStatus":"unaffected","versions":[{"version":"1.7.7","status":"affected","lessThan":"1.11.13","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:*"],"modules":["jose_jwk_kty_rsa","jose_jwk","'Elixir.JOSE.JWK'"],"programFiles":["src/jwk/jose_jwk_kty_rsa.erl","src/jwk/jose_jwk.erl","lib/jose/jwk.ex"],"programRoutines":[{"name":"jose_jwk_kty_rsa:from_map/1"},{"name":"jose_jwk_kty_rsa:convert_sfm_to_crt/1"},{"name":"jose_jwk_kty_rsa:convert_sfm_to_crt_find_p/6"},{"name":"jose_jwk:from_binary/1"},{"name":"jose_jwk:from_map/1"},{"name":"'Elixir.JOSE.JWK':from_binary/1"},{"name":"'Elixir.JOSE.JWK':from_map/1"}],"repo":"https://github.com/potatosalad/erlang-jose"},{"vendor":"potatosalad","product":"jose","packageName":"potatosalad/erlang-jose","packageURL":"pkg:github/potatosalad/erlang-jose","defaultStatus":"unaffected","versions":[{"version":"d19e1ba68d88c68d29aa942be2573a22dbafca1f","status":"affected","lessThan":"bfd336c0062bff93e65d08c22361897e96afd956","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:*"],"modules":["jose_jwk_kty_rsa","jose_jwk","'Elixir.JOSE.JWK'"],"programFiles":["src/jwk/jose_jwk_kty_rsa.erl","src/jwk/jose_jwk.erl","lib/jose/jwk.ex"],"programRoutines":[{"name":"jose_jwk_kty_rsa:from_map/1"},{"name":"jose_jwk_kty_rsa:convert_sfm_to_crt/1"},{"name":"jose_jwk_kty_rsa:convert_sfm_to_crt_find_p/6"},{"name":"jose_jwk:from_binary/1"},{"name":"jose_jwk:from_map/1"},{"name":"'Elixir.JOSE.JWK':from_binary/1"},{"name":"'Elixir.JOSE.JWK':from_map/1"}],"repo":"https://github.com/potatosalad/erlang-jose"}],"references":[{"url":"https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-3m45-vrpj-xmrq","tags":["vendor-advisory","related"]},{"url":"https://cna.erlef.org/cves/CVE-2026-65631.html","name":"EEF CNA record for CVE-2026-65631","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-65631","name":"OSV record EEF-CVE-2026-65631","tags":["related"]},{"url":"https://github.com/potatosalad/erlang-jose/commit/d19e1ba68d88c68d29aa942be2573a22dbafca1f","name":"Introducing commit d19e1ba in potatosalad/erlang-jose","tags":["related"]},{"url":"https://github.com/potatosalad/erlang-jose/commit/bfd336c0062bff93e65d08c22361897e96afd956","name":"Fix commit bfd336c in potatosalad/erlang-jose","tags":["patch"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"LOCAL","baseScore":6.9,"baseSeverity":"MEDIUM","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-407","description":"CWE-407 Inefficient Algorithmic Complexity","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-10-26T19:53:45.204Z"},"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:*","versionEndExcluding":"1.11.13","versionStartIncluding":"1.7.7","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"AND"}],"credits":[{"lang":"en","type":"reporter","value":"Peter Ullrich"},{"lang":"en","type":"remediation developer","value":"Andrew Bennett"},{"lang":"en","type":"analyst","value":"Jonatan Männchen / EEF"}],"impacts":[{"capecId":"CAPEC-130","descriptions":[{"lang":"en","value":"CAPEC-130 Excessive Allocation"}]}],"source":{"discovery":"EXTERNAL"}}}}}