{"cve":"CVE-2025-52556","nvd":{"published":"2025-06-21T02:15:19.947","modified":"2026-06-17T09:36:40.210","status":"Deferred","description":"rfc3161-client is a Python library implementing the Time-Stamp Protocol (TSP) described in RFC 3161. Prior to version 1.0.3, there is a flaw in the timestamp response signature verification logic. In particular, chain verification is performed against the TSR's embedded certificates up to the trusted root(s), but fails to verify the TSR's own signature against the timestamping leaf certificates. Consequently, vulnerable versions perform insufficient signature validation to properly consider a TSR verified, as the attacker can introduce any TSR signature so long as the embedded leaf chains up to some root TSA. This issue has been patched in version 1.0.3. There is no workaround for this issue.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","score":9.3},"cvss_v3":null,"cwes":["CWE-347"],"references":["https://github.com/trailofbits/rfc3161-client/commit/724a184f953e3f171f85cb223871172b41b0d0dc","https://github.com/trailofbits/rfc3161-client/security/advisories/GHSA-6qhv-4h7r-2g9m"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:03:23.287444849+00:00"},"epss":{"cve":"CVE-2025-52556","score":0.00169,"percentile":0.06232,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-6qhv-4h7r-2g9m","url":"https://osv.dev/vulnerability/GHSA-6qhv-4h7r-2g9m","summary":"rfc3161-client has insufficient verification for timestamp response signatures","modified":"2026-06-29T12:26:08.261502687Z","packages":[{"ecosystem":"PyPI","name":"rfc3161-client","purl":"pkg:pypi/rfc3161-client","ranges":["<1.0.3"],"fixed":["1.0.3"]}]},{"id":"PYSEC-2026-525","url":"https://osv.dev/vulnerability/PYSEC-2026-525","summary":"rfc3161-client has insufficient verification for timestamp response signatures","modified":"2026-07-13T16:15:34.044532111Z","packages":[{"ecosystem":"PyPI","name":"rfc3161-client","purl":"pkg:pypi/rfc3161-client","ranges":["<1.0.3"],"fixed":["1.0.3"]}]}],"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."]}