{"id":"CVE-2025-48995","summary":"SignXML's signature verification with HMAC is vulnerable to a timing attack","details":"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.","aliases":["GHSA-gmhf-gg8w-jw42","PYSEC-2026-1922"],"modified":"2026-08-12T03:51:25.251278703Z","published":"2025-06-02T16:23:27.706Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/48xxx/CVE-2025-48995.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-208"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/48xxx/CVE-2025-48995.json"},{"type":"ADVISORY","url":"https://github.com/XML-Security/signxml/security/advisories/GHSA-gmhf-gg8w-jw42"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-48995"},{"type":"FIX","url":"https://github.com/XML-Security/signxml/commit/1b501faaacf34cf978a52dbc6915ec11e27611cd"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/xml-security/signxml","events":[{"introduced":"0"},{"fixed":"1b501faaacf34cf978a52dbc6915ec11e27611cd"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"4.0.4"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v4.0.3","v4.0.2","v4.0.1","v4.0.0","v3.2.2","v3.2.1","v3.2.0","v3.1.1","v3.1.0","v3.0.2","v3.0.1","v3.0.0","v2.10.1","v2.10.0","v2.9.0","v2.8.2","v2.8.1","v2.8.0","v2.7.3","v2.7.2","v2.7.1","v2.7.0","v2.6.0","v2.5.2","v2.5.1","v2.5.0","v2.4.0","v2.3.0","v2.2.6","v2.2.5","v2.2.4","v2.2.3","v2.2.2","v2.2.1","v2.2.0","v2.1.4","v2.1.3","v2.1.2","v2.1.1","v2.1.0","v2.0.0","v1.0.2","v1.0.1","v1.0.0","v0.6.0","v0.5.0","v0.4.6","v0.4.5","v0.4.4","v0.4.2","v0.4.1","v0.4.0","v0.3.9","v0.3.8","v0.3.7","v0.3.6","v0.3.5","v0.3.4","v0.3.3","v0.3.2","v0.3.1","v0.3.0","v0.2.8","v0.2.7","v0.2.6","v0.2.5","v0.2.4","v0.2.3","v0.2.2","v0.2.0","v0.1.9","v0.1.8","v0.1.7","v0.1.6","v0.1.5","v0.1.4","v0.1.3","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-48995.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}