{"id":"CVE-2026-86219","state":"PUBLISHED","title":"Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step","description":"Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step.\n\nserver_start generates a fresh nonce and sends it in the challenge, and nothing later compares that value against the nonce the client returns. server_step derives the expected digest from the client's own parameters, so a response verifies whenever its digest matches the nonce it carries. The count table it also checks is keyed on the client-supplied nonce and starts empty in each new server object, so a captured first response, carrying `nc=00000001`, passes that too. RFC 2831 defines the nonce in the response as the value the server sent in the preceding challenge.\n\nAn attacker who observes one successful `qop=auth` exchange can replay the captured response against a later session for the same service, host, realm and user, and authenticate as that user without knowing the password.","publishedAt":"2026-09-06T17:46:30.340Z","updatedAt":"2026-09-08T18:54:55.841Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"CISA-ADP"},"assigner":"CPANSec","products":["Authen-SASL"],"affected":[{"packageName":"Authen-SASL","packageURL":"pkg:cpan/Authen-SASL","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"2.2100","versionType":"custom"}],"collectionURL":"https://cpan.org/modules","modules":["Authen::SASL::Perl::DIGEST_MD5"],"programFiles":["lib/Authen/SASL/Perl/DIGEST_MD5.pm"],"programRoutines":[{"name":"Authen::SASL::Perl::DIGEST_MD5::server_step"},{"name":"Authen::SASL::Perl::DIGEST_MD5::server_start"}],"repo":"https://github.com/perl-authen-sasl/perl-authen-sasl"}],"references":["https://metacpan.org/release/EHUELS/Authen-SASL-2.2000/source/lib/Authen/SASL/Perl/DIGEST_MD5.pm#L203-222","https://metacpan.org/release/EHUELS/Authen-SASL-2.2000/source/lib/Authen/SASL/Perl/DIGEST_MD5.pm#L410-414","https://datatracker.ietf.org/doc/html/rfc2831#section-2.1.2","https://github.com/perl-authen-sasl/perl-authen-sasl/commit/94337367030612842924f697cead29964a96448d.patch","https://metacpan.org/release/EHUELS/Authen-SASL-2.2100/changes","https://www.cve.org/CVERecord?id=CVE-2025-40918"],"weaknesses":["CWE-294"],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/86xxx/CVE-2026-86219.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-86219","state":"PUBLISHED","datePublished":"2026-09-06T17:46:30.340Z","dateUpdated":"2026-09-08T18:54:55.841Z","assignerShortName":"CPANSec","assignerOrgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","dateReserved":"2026-09-06T00:13:35.358Z"},"containers":{"cna":{"title":"Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step","descriptions":[{"lang":"en","value":"Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step.\n\nserver_start generates a fresh nonce and sends it in the challenge, and nothing later compares that value against the nonce the client returns. server_step derives the expected digest from the client's own parameters, so a response verifies whenever its digest matches the nonce it carries. The count table it also checks is keyed on the client-supplied nonce and starts empty in each new server object, so a captured first response, carrying `nc=00000001`, passes that too. RFC 2831 defines the nonce in the response as the value the server sent in the preceding challenge.\n\nAn attacker who observes one successful `qop=auth` exchange can replay the captured response against a later session for the same service, host, realm and user, and authenticate as that user without knowing the password."}],"affected":[{"packageName":"Authen-SASL","packageURL":"pkg:cpan/Authen-SASL","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"2.2100","versionType":"custom"}],"collectionURL":"https://cpan.org/modules","modules":["Authen::SASL::Perl::DIGEST_MD5"],"programFiles":["lib/Authen/SASL/Perl/DIGEST_MD5.pm"],"programRoutines":[{"name":"Authen::SASL::Perl::DIGEST_MD5::server_step"},{"name":"Authen::SASL::Perl::DIGEST_MD5::server_start"}],"repo":"https://github.com/perl-authen-sasl/perl-authen-sasl"}],"references":[{"url":"https://metacpan.org/release/EHUELS/Authen-SASL-2.2000/source/lib/Authen/SASL/Perl/DIGEST_MD5.pm#L203-222"},{"url":"https://metacpan.org/release/EHUELS/Authen-SASL-2.2000/source/lib/Authen/SASL/Perl/DIGEST_MD5.pm#L410-414"},{"url":"https://datatracker.ietf.org/doc/html/rfc2831#section-2.1.2"},{"url":"https://github.com/perl-authen-sasl/perl-authen-sasl/commit/94337367030612842924f697cead29964a96448d.patch","tags":["patch"]},{"url":"https://metacpan.org/release/EHUELS/Authen-SASL-2.2100/changes","tags":["release-notes"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-40918","tags":["related"]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-294","description":"CWE-294 Authentication Bypass by Capture-replay","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"CPANSec","orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","dateUpdated":"2026-09-06T17:46:30.340Z"},"impacts":[{"capecId":"CAPEC-115","descriptions":[{"lang":"en","value":"CAPEC-115 Authentication Bypass"}]}],"solutions":[{"lang":"en","value":"Upgrade to Authen-SASL 2.2100 or later."}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"cpansec-cna-tool 0.1"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":9.8,"attackVector":"NETWORK","baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-09-08T18:54:38.530817Z","id":"CVE-2026-86219","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-08T18:54:55.841Z"}}]}}}