{"id":"UBUNTU-CVE-2025-48995","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.","modified":"2026-05-20T16:23:32.677215597Z","published":"2025-06-02T17:15:00Z","upstream":["CVE-2025-48995"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2025-48995"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2025-48995"},{"type":"REPORT","url":"https://github.com/XML-Security/signxml/security/advisories/GHSA-gmhf-gg8w-jw42"},{"type":"REPORT","url":"https://github.com/XML-Security/signxml/commit/1b501faaacf34cf978a52dbc6915ec11e27611cd"}],"affected":[{"package":{"name":"python-signxml","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/python-signxml?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.3+dfsg-1","4.0.5+dfsg-1","4.0.5+dfsg-2"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-signxml","binary_version":"4.0.5+dfsg-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-48995.json"}},{"package":{"name":"python-signxml","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/python-signxml?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.5+dfsg-2","4.2.0+dfsg-1"],"ecosystem_specific":{"binaries":[{"binary_version":"4.2.0+dfsg-1","binary_name":"python3-signxml"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-48995.json"}}],"schema_version":"1.7.5","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"},{"type":"Ubuntu","score":"medium"}]}