{"cve":"CVE-2026-49852","nvd":{"published":"2026-07-17T20:17:23.270","modified":"2026-10-24T20:10:00.137","status":"Deferred","description":"joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.6.8, joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the caller-supplied verification key is the empty string or None, because HMACAlgorithm.sign and HMACAlgorithm.verify in src/joserfc/_rfc7518/jws_algs.py pass the output of OctKey.get_op_key(...) to hmac.new(...) and OctKey.import_key in src/joserfc/_rfc7518/oct_key.py only emits a SecurityWarning for keys shorter than 14 bytes without rejecting zero-length input. This issue is fixed in version 1.6.8.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","score":8.7},"cvss_v3":null,"cwes":["CWE-287","CWE-326","CWE-1391"],"references":["https://github.com/authlib/joserfc/commit/86d00910b2b2d2d07503fee9b572906daefab7f1","https://github.com/authlib/joserfc/releases/tag/1.6.8","https://github.com/authlib/joserfc/security/advisories/GHSA-gg9x-qcx2-xmrh","https://github.com/authlib/joserfc/security/advisories/GHSA-gg9x-qcx2-xmrh"],"products":[],"source":"nvd","synced_at":"2026-10-25T17:50:08.599881581+00:00"},"epss":{"cve":"CVE-2026-49852","score":0.00171,"percentile":0.06448,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-gg9x-qcx2-xmrh","url":"https://osv.dev/vulnerability/GHSA-gg9x-qcx2-xmrh","summary":"joserfc: HS256/HS384/HS512 verify accepts empty/nil HMAC key (cross-language sibling of CVE-2026-45363)","modified":"2026-09-10T03:50:52.107071179Z","packages":[{"ecosystem":"PyPI","name":"joserfc","purl":"pkg:pypi/joserfc","ranges":["<1.6.8"],"fixed":["1.6.8"]}]},{"id":"PYSEC-2026-2528","url":"https://osv.dev/vulnerability/PYSEC-2026-2528","summary":"joserfc: HS256/HS384/HS512 verify accepts empty/nil HMAC key (cross-language sibling of CVE-2026-45363)","modified":"2026-07-13T16:31:58.665037685Z","packages":[{"ecosystem":"PyPI","name":"joserfc","purl":"pkg:pypi/joserfc","ranges":["<1.6.8"],"fixed":["1.6.8"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}