{"cve":"CVE-2025-48995","nvd":{"published":"2025-06-02T17:15:41.063","modified":"2026-06-17T09:30:38.297","status":"Deferred","description":"SignXML is an implementation of the W3C XML Signature standard in Python. When verifying signatures with X509 certificate validation turned off and HMAC shared secret set (`signxml.XMLVerifier.verify(require_x509=False, hmac_key=...`), versions of SignXML prior to 4.0.4 are vulnerable to a potential timing attack. The verifier may leak information about the correct HMAC when comparing it with the user supplied hash, allowing users to reconstruct the correct HMAC for any data.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","score":6.9},"cvss_v3":null,"cwes":["CWE-208"],"references":["https://github.com/XML-Security/signxml/commit/1b501faaacf34cf978a52dbc6915ec11e27611cd","https://github.com/XML-Security/signxml/security/advisories/GHSA-gmhf-gg8w-jw42"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:02:23.998251710+00:00"},"epss":{"cve":"CVE-2025-48995","score":0.00239,"percentile":0.15069,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-gmhf-gg8w-jw42","url":"https://osv.dev/vulnerability/GHSA-gmhf-gg8w-jw42","summary":"SignXML's signature verification with HMAC is vulnerable to a timing attack","modified":"2026-07-07T17:56:23.298719018Z","packages":[{"ecosystem":"PyPI","name":"signxml","purl":"pkg:pypi/signxml","ranges":["<4.0.4"],"fixed":["4.0.4"]}]},{"id":"PYSEC-2026-1922","url":"https://osv.dev/vulnerability/PYSEC-2026-1922","summary":"SignXML's signature verification with HMAC is vulnerable to a timing attack","modified":"2026-07-07T17:48:12.603963915Z","packages":[{"ecosystem":"PyPI","name":"signxml","purl":"pkg:pypi/signxml","ranges":["<4.0.4"],"fixed":["4.0.4"]}]}],"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."]}