{"id":"UBUNTU-CVE-2026-65626","details":"The pure-Erlang RSAES-PKCS1-v1_5 decryption in the jose_jwa_pkcs1 module is a Bleichenbacher padding oracle. eme_pkcs1_decode/2 returns the recovered message when a decrypted block has valid PKCS#1 v1.5 padding (a leading 0x00 0x02, a padding string of at least eight non-zero bytes, and a 0x00 separator) and returns a distinct error result otherwise, and rsaes_pkcs1_decrypt/2 additionally returns {error, {badsize, _}} when the length check fails. The implementation applies no implicit-rejection countermeasure (RFC 8017 §7.2.2): it does not substitute a deterministic pseudo-random plaintext on a padding failure, so a one-bit padding-conformance signal leaks to the caller. Because the underlying modular exponentiation in dp/2 is a raw, non-blinded crypto:mod_pow/3, the padding check also stays distinguishable by timing even when an application normalizes every failure to a single error value. An unauthenticated attacker who knows only the public RSA key and can submit ciphertexts to a decryption endpoint that unwraps RSA1_5 JWE keys (or otherwise calls decrypt_private/3 with rsa_pkcs1_padding) can use this oracle to recover the plaintext of intercepted ciphertexts, such as content-encryption keys and thus the protected message, or to forge signatures, through roughly 10^4 to 10^6 adaptive chosen-ciphertext queries. This issue affects jose: from 1.3.0 before 1.11.13.","modified":"2026-10-28T20:17:48.029536540Z","published":"2026-10-26T20:17:00Z","upstream":["CVE-2026-65626"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-65626"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-65626"},{"type":"REPORT","url":"https://cna.erlef.org/cves/cve-2026-65626.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/0eac8cef9aaa48fb6846f4e47a0002dc4a73966d"},{"type":"REPORT","url":"https://github.com/potatosalad/erlang-jose/commit/853c5d4c4c0bd2a7ecb055b237f4284184e176c8"},{"type":"REPORT","url":"https://github.com/potatosalad/erlang-jose/security/advisories/ghsa-vwvr-f994-6j9j"},{"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-2026-65626.json"},{"type":"REPORT","url":"https://nvd.nist.gov/vuln/detail/cve-2026-65626"},{"type":"REPORT","url":"https://osv.dev/vulnerability/eef-cve-2026-65626"}],"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_name":"jose","binary_version":"10-2build1"},{"binary_name":"libjose0","binary_version":"10-2build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65626.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-2026-65626.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-2026-65626.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_name":"jose","binary_version":"13-1"},{"binary_name":"libjose0","binary_version":"13-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65626.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-2026-65626.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_version":"14-2build1","binary_name":"jose"},{"binary_version":"14-2build1","binary_name":"libjose0"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65626.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}