{"id":"CVE-2026-56016","state":"PUBLISHED","title":"CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources","description":"CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources.\n\nThe generate_id method builds the session id from a MD5 digest of the process id, the epoch time, and the built-in rand() function. All three are predictable, low-entropy sources: the PID is drawn from a small range, the epoch time can be guessed or read from the HTTP Date header, and Perl's rand() is unsuitable for security purposes because it is predictable and reversible.\n\nAn attacker who predicts a session id can impersonate the corresponding session and bypass authentication.","publishedAt":"2026-07-01T06:46:23.589Z","updatedAt":"2026-07-01T17:36:49.480Z","severity":{"score":5.9,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","source":"CISA-ADP"},"assigner":"CPANSec","products":["MARKSTOS CGI::Session::ID::md5"],"affected":[{"vendor":"MARKSTOS","product":"CGI::Session::ID::md5","packageName":"CGI-Session","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"4.49","versionType":"custom"}],"collectionURL":"https://cpan.org/modules","programFiles":["lib/CGI/Session/ID/md5.pm"],"programRoutines":[{"name":"CGI::Session::ID::md5::generate_id"}],"repo":"http://github.com/cromedome/cgi-session"}],"references":["https://metacpan.org/release/MARKSTOS/CGI-Session-4.49/changes","https://metacpan.org/release/MARKSTOS/CGI-Session-4.49/source/lib/CGI/Session/ID/md5.pm","http://www.openwall.com/lists/oss-security/2026/07/01/6"],"weaknesses":["CWE-340","CWE-338"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/56xxx/CVE-2026-56016.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-56016","state":"PUBLISHED","datePublished":"2026-07-01T06:46:23.589Z","dateUpdated":"2026-07-01T17:36:49.480Z","assignerShortName":"CPANSec","assignerOrgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","dateReserved":"2026-06-18T11:27:09.117Z"},"containers":{"cna":{"title":"CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources","descriptions":[{"lang":"en","value":"CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources.\n\nThe generate_id method builds the session id from a MD5 digest of the process id, the epoch time, and the built-in rand() function. All three are predictable, low-entropy sources: the PID is drawn from a small range, the epoch time can be guessed or read from the HTTP Date header, and Perl's rand() is unsuitable for security purposes because it is predictable and reversible.\n\nAn attacker who predicts a session id can impersonate the corresponding session and bypass authentication."}],"affected":[{"vendor":"MARKSTOS","product":"CGI::Session::ID::md5","packageName":"CGI-Session","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"4.49","versionType":"custom"}],"collectionURL":"https://cpan.org/modules","programFiles":["lib/CGI/Session/ID/md5.pm"],"programRoutines":[{"name":"CGI::Session::ID::md5::generate_id"}],"repo":"http://github.com/cromedome/cgi-session"}],"references":[{"url":"https://metacpan.org/release/MARKSTOS/CGI-Session-4.49/changes","tags":["release-notes"]},{"url":"https://metacpan.org/release/MARKSTOS/CGI-Session-4.49/source/lib/CGI/Session/ID/md5.pm","tags":["related"]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-340","description":"CWE-340 Generation of Predictable Numbers or Identifiers","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-338","description":"CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"CPANSec","orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","dateUpdated":"2026-07-01T06:46:23.589Z"},"impacts":[{"capecId":"CAPEC-59","descriptions":[{"lang":"en","value":"CAPEC-59 Session Credential Falsification through Prediction"}]},{"capecId":"CAPEC-115","descriptions":[{"lang":"en","value":"CAPEC-115 Authentication Bypass"}]}],"solutions":[{"lang":"en","value":"Upgrade to CGI::Session 4.49 or later, which generates session ids from Crypt::SysRandom."}],"source":{"discovery":"UNKNOWN"},"timeline":[{"lang":"en","time":"2026-06-30T00:00:00.000Z","value":"Version 4.49 released with fix."}],"x_generator":{"engine":"cpansec-cna-tool 0.1"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.9,"attackVector":"NETWORK","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"HIGH","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-07-01T14:03:10.013809Z","id":"CVE-2026-56016","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-01T14:03:16.730Z"}},{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/07/01/6"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-07-01T17:36:49.480Z"}}]}}}