{"id":"CVE-2025-48995","state":"PUBLISHED","title":"SignXML's signature verification with HMAC is vulnerable to a timing attack","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.","publishedAt":"2025-06-02T16:23:27.706Z","updatedAt":"2025-06-02T16:41:13.270Z","severity":{"score":6.9,"label":"Medium","version":"4.0","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","source":"GitHub_M"},"assigner":"GitHub_M","products":["XML-Security signxml"],"affected":[{"vendor":"XML-Security","product":"signxml","versions":[{"version":"< 4.0.4","status":"affected"}]}],"references":["https://github.com/XML-Security/signxml/security/advisories/GHSA-gmhf-gg8w-jw42","https://github.com/XML-Security/signxml/commit/1b501faaacf34cf978a52dbc6915ec11e27611cd"],"weaknesses":["CWE-208"],"ingestedAt":"2026-10-29T20:09:23.771Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/48xxx/CVE-2025-48995.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2025-48995","state":"PUBLISHED","datePublished":"2025-06-02T16:23:27.706Z","dateUpdated":"2025-06-02T16:41:13.270Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2025-05-29T16:34:07.174Z"},"containers":{"cna":{"title":"SignXML's signature verification with HMAC is vulnerable to a timing attack","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"XML-Security","product":"signxml","versions":[{"version":"< 4.0.4","status":"affected"}]}],"references":[{"url":"https://github.com/XML-Security/signxml/security/advisories/GHSA-gmhf-gg8w-jw42","name":"https://github.com/XML-Security/signxml/security/advisories/GHSA-gmhf-gg8w-jw42","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/XML-Security/signxml/commit/1b501faaacf34cf978a52dbc6915ec11e27611cd","name":"https://github.com/XML-Security/signxml/commit/1b501faaacf34cf978a52dbc6915ec11e27611cd","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-208","lang":"en","description":"CWE-208: Observable Timing Discrepancy","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2025-06-02T16:23:27.706Z"},"source":{"advisory":"GHSA-gmhf-gg8w-jw42","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2025-06-02T16:40:57.602093Z","id":"CVE-2025-48995","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-06-02T16:41:13.270Z"}}]}}}