CVE-2026-56016
CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources.
The 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.
An attacker who predicts a session id can impersonate the corresponding session and bypass authentication.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Puntuación base: 5.9
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.51%
- Percentil entre todas las CVEs puntuadas: 42
- Fecha de la puntuación: 4/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-338, CWE-340
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-56016",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-56016",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-07-01T14:03:10.013809Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"cvssData": {
"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"
},
"impactScore": 3.6,
"exploitabilityScore": 2.2
}
]
},
"affected": [
{
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
"affectedData": [
{
"repo": "http://github.com/cromedome/cgi-session",
"vendor": "MARKSTOS",
"product": "CGI::Session::ID::md5",
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "4.49",
"versionType": "custom"
}
],
"packageName": "CGI-Session",
"programFiles": [
"lib/CGI/Session/ID/md5.pm"
],
"collectionURL": "https://cpan.org/modules",
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "CGI::Session::ID::md5::generate_id"
}
]
}
]
}
],
"published": "2026-07-01T08:16:21.883",
"references": [
{
"url": "https://metacpan.org/release/MARKSTOS/CGI-Session-4.49/changes",
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
},
{
"url": "https://metacpan.org/release/MARKSTOS/CGI-Session-4.49/source/lib/CGI/Session/ID/md5.pm",
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
},
{
"url": "http://www.openwall.com/lists/oss-security/2026/07/01/6",
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
"description": [
{
"lang": "en",
"value": "CWE-338"
},
{
"lang": "en",
"value": "CWE-340"
}
]
}
],
"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."
}
],
"lastModified": "2026-07-02T17:39:57.427",
"sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
}