{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-75870","assignerOrgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","state":"PUBLISHED","assignerShortName":"CPANSec","dateReserved":"2026-08-18T11:59:49.642Z","datePublished":"2026-08-22T13:35:58.346Z","dateUpdated":"2026-08-25T19:28:36.443Z"},"containers":{"cna":{"affected":[{"collectionURL":"https://cpan.org/modules","defaultStatus":"unaffected","modules":["Punk"],"packageName":"Punk","packageURL":"pkg:cpan/Punk","programFiles":["xs/app.xs","include/punk/punk_session.h"],"programRoutines":[{"name":"Punk::App::session"},{"name":"ps_load"},{"name":"ps_writeback"}],"versions":[{"lessThan":"0.18","status":"affected","version":"0","versionType":"custom"}]}],"descriptions":[{"lang":"en","value":"Punk versions before 0.18 for Perl allow session cookie forgery via an empty default HMAC key when a session is declared without a secret.\n\nThe session keyword freezes its options onto the application as given: it does not require a secret, warn, or refuse to start when one is absent. The cookie read and the write-back both default that key to the empty string, so a declaration with no secret option, or with an undefined or empty one, signs and verifies with a zero-length HMAC-SHA256 key.\n\nAn attacker who knows the cookie format can then mint one offline carrying any contents the session holds, such as a user identifier or a role. Nothing marks the misconfiguration at runtime: cookies are well formed and sessions round-trip as expected."}],"problemTypes":[{"descriptions":[{"cweId":"CWE-1394","description":"CWE-1394 Use of Default Cryptographic Key","lang":"en","type":"CWE"}]}],"providerMetadata":{"orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","shortName":"CPANSec","dateUpdated":"2026-08-22T13:35:58.346Z"},"references":[{"tags":["technical-description"],"url":"https://metacpan.org/release/LNATION/Punk-0.17/source/include/punk/punk_session.h"},{"tags":["technical-description"],"url":"https://metacpan.org/release/LNATION/Punk-0.17/view/lib/Punk.pm"},{"tags":["release-notes"],"url":"https://metacpan.org/release/LNATION/Punk-0.18/source/Changes"}],"solutions":[{"lang":"en","value":"Upgrade to Punk 0.18 or later."}],"source":{"discovery":"UNKNOWN"},"title":"Punk versions before 0.18 for Perl allow session cookie forgery via an empty default HMAC key when a session is declared without a secret","workarounds":[{"lang":"en","value":"For deployments that cannot upgrade to 0.18, declare the session keyword with a non-empty secret. The secret keyword fails closed, so sourcing the key through it turns a missing configuration path or an unset environment variable into a startup error."}],"x_generator":{"engine":"cpansec-cna-tool 0.1"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/08/22/5"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2026-08-22T19:07:10.053Z"}},{"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":9.1,"attackVector":"NETWORK","baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-08-25T19:27:34.454527Z","id":"CVE-2026-75870","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-25T19:28:36.443Z"}}]}}