{"cve":"CVE-2026-27932","nvd":{"published":"2026-03-03T23:15:56.050","modified":"2026-06-17T10:27:55.770","status":"Analyzed","description":"joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In 1.6.2 and earlier, a resource exhaustion vulnerability in joserfc allows an unauthenticated attacker to cause a Denial of Service (DoS) via CPU exhaustion. When the library decrypts a JSON Web Encryption (JWE) token using Password-Based Encryption (PBES2) algorithms, it reads the p2c (PBES2 Count) parameter directly from the token's protected header. This parameter defines the number of iterations for the PBKDF2 key derivation function. Because joserfc does not validate or bound this value, an attacker can specify an extremely large iteration count (e.g., 2^31 - 1), forcing the server to expend massive CPU resources processing a single token. This vulnerability exists at the JWA layer and impacts all high-level JWE and JWT decryption interfaces if PBES2 algorithms are allowed by the application's policy.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-770"],"references":["https://github.com/authlib/joserfc/commit/696a9611ab982c45ee2190ed79ca8e1d8e09398f","https://github.com/authlib/joserfc/security/advisories/GHSA-w5r5-m38g-f9f9"],"products":["hsiaoming:joserfc"],"source":"nvd","synced_at":"2026-10-19T22:24:17.937441719+00:00"},"epss":{"cve":"CVE-2026-27932","score":0.00462,"percentile":0.40026,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-w5r5-m38g-f9f9","url":"https://osv.dev/vulnerability/GHSA-w5r5-m38g-f9f9","summary":"joserfc's PBES2 p2c Unbounded Iteration Count enables Denial of Service (DoS)","modified":"2026-09-10T03:50:41.369045046Z","packages":[{"ecosystem":"PyPI","name":"joserfc","purl":"pkg:pypi/joserfc","ranges":["<1.6.3"],"fixed":["1.6.3"]}]},{"id":"PYSEC-2026-2529","url":"https://osv.dev/vulnerability/PYSEC-2026-2529","summary":"joserfc's PBES2 p2c Unbounded Iteration Count enables Denial of Service (DoS)","modified":"2026-07-13T16:31:58.664671173Z","packages":[{"ecosystem":"PyPI","name":"joserfc","purl":"pkg:pypi/joserfc","ranges":["<1.6.3"],"fixed":["1.6.3"]}]}],"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."]}