{"id":"UBUNTU-CVE-2026-65631","details":"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.","modified":"2026-10-28T01:07:39.866581859Z","published":"2026-10-27T00:00:00Z","upstream":["CVE-2026-65631"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-65631"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-65631"},{"type":"REPORT","url":"https://cna.erlef.org/cves/cve-2026-65631.html"},{"type":"REPORT","url":"https://github.com"},{"type":"REPORT","url":"https://github.com/potatosalad/erlang-jose"},{"type":"REPORT","url":"https://github.com/potatosalad/erlang-jose/commit/bfd336c0062bff93e65d08c22361897e96afd956"},{"type":"REPORT","url":"https://github.com/potatosalad/erlang-jose/commit/d19e1ba68d88c68d29aa942be2573a22dbafca1f"},{"type":"REPORT","url":"https://github.com/potatosalad/erlang-jose/security/advisories/ghsa-3m45-vrpj-xmrq"},{"type":"REPORT","url":"https://hex.pm/packages/jose"},{"type":"REPORT","url":"https://repo.hex.pm"},{"type":"REPORT","url":"https://github.com/cveproject/cvelistv5/tree/main/cves/2026/65xxx/cve-2026-65631.json"},{"type":"REPORT","url":"https://nvd.nist.gov/vuln/detail/cve-2026-65631"},{"type":"REPORT","url":"https://osv.dev/vulnerability/eef-cve-2026-65631"}],"affected":[{"package":{"name":"jose","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/jose?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["10-2","10-2build1"],"ecosystem_specific":{"binaries":[{"binary_version":"10-2build1","binary_name":"jose"},{"binary_name":"libjose0","binary_version":"10-2build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65631.json"}},{"package":{"name":"jose","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/jose?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["10-2build2"],"ecosystem_specific":{"binaries":[{"binary_version":"10-2build2","binary_name":"jose"},{"binary_name":"libjose0","binary_version":"10-2build2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65631.json"}},{"package":{"name":"jose","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/jose?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["10-3","11-2"],"ecosystem_specific":{"binaries":[{"binary_version":"11-2","binary_name":"jose"},{"binary_name":"libjose0","binary_version":"11-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65631.json"}},{"package":{"name":"jose","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/jose?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["11-2","11-3","11-3build1","11-3build2","13-1"],"ecosystem_specific":{"binaries":[{"binary_version":"13-1","binary_name":"jose"},{"binary_name":"libjose0","binary_version":"13-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65631.json"}},{"package":{"name":"jose","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/jose?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["14-2build1","14-2build2"],"ecosystem_specific":{"binaries":[{"binary_name":"jose","binary_version":"14-2build2"},{"binary_name":"libjose0","binary_version":"14-2build2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65631.json"}},{"package":{"name":"jose","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/jose?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["14-2build1"],"ecosystem_specific":{"binaries":[{"binary_name":"jose","binary_version":"14-2build1"},{"binary_version":"14-2build1","binary_name":"libjose0"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65631.json"}}],"schema_version":"1.9.2","severity":[{"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"},{"type":"Ubuntu","score":"medium"}]}