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.
\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.
This issue affects jose: from 1.7.7 before 1.11.13.
" }, { "base64": false, "type": "text/markdown", "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." } ], "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." } ], "impacts": [ { "capecId": "CAPEC-130", "descriptions": [ { "lang": "en", "value": "CAPEC-130 Excessive Allocation" } ] } ], "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": { "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-10-26T19:53:45.204Z" }, "references": [ { "tags": [ "vendor-advisory", "related" ], "url": "https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-3m45-vrpj-xmrq" }, { "name": "EEF CNA record for CVE-2026-65631", "tags": [ "related" ], "url": "https://cna.erlef.org/cves/CVE-2026-65631.html" }, { "name": "OSV record EEF-CVE-2026-65631", "tags": [ "related" ], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-65631" }, { "name": "Introducing commit d19e1ba in potatosalad/erlang-jose", "tags": [ "related" ], "url": "https://github.com/potatosalad/erlang-jose/commit/d19e1ba68d88c68d29aa942be2573a22dbafca1f" }, { "name": "Fix commit bfd336c in potatosalad/erlang-jose", "tags": [ "patch" ], "url": "https://github.com/potatosalad/erlang-jose/commit/bfd336c0062bff93e65d08c22361897e96afd956" } ], "source": { "discovery": "EXTERNAL" }, "title": "erlang-jose RSA JWK parsing attempts to factor an attacker-controlled modulus, enabling CPU-exhaustion denial of service" } } }