{"api_version":"1","generated_at":"2026-08-14T18:45:02+00:00","cve":"CVE-2026-18568","urls":{"html":"https://cve.report/CVE-2026-18568","api":"https://cve.report/api/cve/CVE-2026-18568.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-18568","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-18568"},"summary":{"title":"XML::Sig versions from 0.29 before 0.72 for Perl allow signature verification bypass because verify returns true when every signature was skipped before any cryptographic check","description":"XML::Sig versions from 0.29 before 0.72 for Perl allow signature verification bypass because verify returns true when every signature was skipped before any cryptographic check.\n\nverify in lib/XML/Sig.pm counts the `//dsig:Signature` elements into `$numsigs` and iterates over them, but two paths reach `next` before any digest or key check runs: a `SignedInfo/Reference/@URI` that resolves to no element while `$numsigs` is greater than 1, and, when `id_attr` is set, a reference that does not match the requested ID. The loop records nothing about what it checked, so when every signature takes one of those paths control reaches the unconditional `return 1` that ends verify. Two `Signature` elements whose Reference URI names an ID that no element carries is enough, as is one such element combined with `id_attr`.\n\nAny caller that passes untrusted XML to verify can receive a true return for a document in which no digest and no signature value was checked; a `cert` or `cert_text` trust anchor does not change this, because no key check runs. Versions up to 0.28 use an XML::XPath based verify that has no such skip and are not affected.","state":"PUBLISHED","assigner":"CPANSec","published_at":"2026-08-03 16:16:28","updated_at":"2026-08-05 14:58:07"},"problem_types":["CWE-347","CWE-347 CWE-347 Improper Verification of Cryptographic Signature"],"metrics":[{"version":"3.1","source":"ADP","type":"DECLARED","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","version":"3.1"}},{"version":"3.1","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE"}}],"references":[{"url":"https://www.cve.org/CVERecord?id=CVE-2025-40934","name":"https://www.cve.org/CVERecord?id=CVE-2025-40934","refsource":"9b29abf9-4ab0-4765-b253-1875cd9b441e","tags":["Not Applicable"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://metacpan.org/release/TIMLEGGE/XML-Sig-0.72/changes","name":"https://metacpan.org/release/TIMLEGGE/XML-Sig-0.72/changes","refsource":"9b29abf9-4ab0-4765-b253-1875cd9b441e","tags":["Release Notes"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/perl-net-saml2/perl-XML-Sig/commit/ef22cfed1ac0f29b316d17eb79cf6480e03ae16a.patch","name":"https://github.com/perl-net-saml2/perl-XML-Sig/commit/ef22cfed1ac0f29b316d17eb79cf6480e03ae16a.patch","refsource":"9b29abf9-4ab0-4765-b253-1875cd9b441e","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-18568","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-18568","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"TIMLEGGE","product":"XML::Sig","version":"affected 0.29 0.72 custom","platforms":[]}],"timeline":[{"source":"CNA","time":"2026-08-03T00:00:00.000Z","lang":"en","value":"Version 0.72 released with fix."}],"solutions":[{"source":"CNA","title":"","value":"Upgrade to XML::Sig 0.72 or later, which returns false when no reference digest was checked and matched.","time":"","lang":"en"}],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2026","cve_id":"18568","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"xml\\","cpe5":"\\","cpe6":"sig_project","cpe7":"xml\\","cpe8":"\\","cpe9":"sig","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"18568","cve":"CVE-2026-18568","epss":"0.001910000","percentile":"0.088930000","score_date":"2026-08-09","updated_at":"2026-08-10 00:07:38"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","version":"3.1"}},{"other":{"content":{"id":"CVE-2026-18568","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-08-03T20:05:13.814301Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-08-03T20:05:52.443Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"collectionURL":"https://cpan.org/modules","defaultStatus":"unaffected","packageName":"XML-Sig","product":"XML::Sig","programFiles":["lib/XML/Sig.pm"],"programRoutines":[{"name":"XML::Sig::verify"}],"repo":"https://github.com/perl-net-saml2/perl-XML-Sig","vendor":"TIMLEGGE","versions":[{"lessThan":"0.72","status":"affected","version":"0.29","versionType":"custom"}]}],"descriptions":[{"lang":"en","value":"XML::Sig versions from 0.29 before 0.72 for Perl allow signature verification bypass because verify returns true when every signature was skipped before any cryptographic check.\n\nverify in lib/XML/Sig.pm counts the `//dsig:Signature` elements into `$numsigs` and iterates over them, but two paths reach `next` before any digest or key check runs: a `SignedInfo/Reference/@URI` that resolves to no element while `$numsigs` is greater than 1, and, when `id_attr` is set, a reference that does not match the requested ID. The loop records nothing about what it checked, so when every signature takes one of those paths control reaches the unconditional `return 1` that ends verify. Two `Signature` elements whose Reference URI names an ID that no element carries is enough, as is one such element combined with `id_attr`.\n\nAny caller that passes untrusted XML to verify can receive a true return for a document in which no digest and no signature value was checked; a `cert` or `cert_text` trust anchor does not change this, because no key check runs. Versions up to 0.28 use an XML::XPath based verify that has no such skip and are not affected."}],"problemTypes":[{"descriptions":[{"cweId":"CWE-347","description":"CWE-347 Improper Verification of Cryptographic Signature","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-08-03T14:38:52.540Z","orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","shortName":"CPANSec"},"references":[{"tags":["patch"],"url":"https://github.com/perl-net-saml2/perl-XML-Sig/commit/ef22cfed1ac0f29b316d17eb79cf6480e03ae16a.patch"},{"tags":["release-notes"],"url":"https://metacpan.org/release/TIMLEGGE/XML-Sig-0.72/changes"},{"tags":["related"],"url":"https://www.cve.org/CVERecord?id=CVE-2025-40934"}],"solutions":[{"lang":"en","value":"Upgrade to XML::Sig 0.72 or later, which returns false when no reference digest was checked and matched."}],"source":{"discovery":"UNKNOWN"},"timeline":[{"lang":"en","time":"2026-08-03T00:00:00.000Z","value":"Version 0.72 released with fix."}],"title":"XML::Sig versions from 0.29 before 0.72 for Perl allow signature verification bypass because verify returns true when every signature was skipped before any cryptographic check","x_generator":{"engine":"cpansec-cna-tool 0.1"}}},"cveMetadata":{"assignerOrgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","assignerShortName":"CPANSec","cveId":"CVE-2026-18568","datePublished":"2026-08-03T14:38:52.540Z","dateReserved":"2026-08-02T00:59:21.745Z","dateUpdated":"2026-08-03T20:05:52.443Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-03 16:16:28","lastModifiedDate":"2026-08-05 14:58:07","problem_types":["CWE-347","CWE-347 CWE-347 Improper Verification of Cryptographic Signature"],"metrics":{"cvssMetricV31":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-08-03T20:05:13.814301Z","id":"CVE-2026-18568","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:xml\\:\\:sig_project:xml\\:\\:sig:*:*:*:*:*:perl:*:*","versionStartIncluding":"0.29","versionEndExcluding":"0.72","matchCriteriaId":"B8BBB154-3467-4332-966C-BC32ED6BD2AD"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"18568","Ordinal":"1","Title":"XML::Sig versions from 0.29 before 0.72 for Perl allow signature","CVE":"CVE-2026-18568","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"18568","Ordinal":"1","NoteData":"XML::Sig versions from 0.29 before 0.72 for Perl allow signature verification bypass because verify returns true when every signature was skipped before any cryptographic check.\n\nverify in lib/XML/Sig.pm counts the `//dsig:Signature` elements into `$numsigs` and iterates over them, but two paths reach `next` before any digest or key check runs: a `SignedInfo/Reference/@URI` that resolves to no element while `$numsigs` is greater than 1, and, when `id_attr` is set, a reference that does not match the requested ID. The loop records nothing about what it checked, so when every signature takes one of those paths control reaches the unconditional `return 1` that ends verify. Two `Signature` elements whose Reference URI names an ID that no element carries is enough, as is one such element combined with `id_attr`.\n\nAny caller that passes untrusted XML to verify can receive a true return for a document in which no digest and no signature value was checked; a `cert` or `cert_text` trust anchor does not change this, because no key check runs. Versions up to 0.28 use an XML::XPath based verify that has no such skip and are not affected.","Type":"Description","Title":"XML::Sig versions from 0.29 before 0.72 for Perl allow signature"}]}}}