CVE-2026-5081
Apache::Session::Generate::ModUniqueId versions from 1.54 through 1.94 for Perl session ids are insecure.
Apache::Session::Generate::ModUniqueId (added in version 1.54) uses the value of the UNIQUE_ID environment variable for the session id. The UNIQUE_ID variable is set by the Apache mod_unique_id plugin, which generates unique ids for the request. The id is based on the IPv4 address, the process id, the epoch time, a 16-bit counter and a thread index, with no obfuscation.
The server IP is often available to the public, and if not available, can be guessed from previous session ids being issued. The process ids may also be guessed from previous session ids. The timestamp is easily guessed (and leaked in the HTTP Date response header).
Read full descriptionShow less
The purpose of mod_unique_id is to assign a unique id to requests so that events can be correlated in different logs. The id is not designed, nor is it suitable for security purposes.
CVSS
- Version: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- Base score: 9.1
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days: 0.49%
- Percentile among all scored CVEs: 40
- Score date: 10/5/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
🎯 ATT&CK techniques
How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.
- Exploitation
T1190Exploit Public-Facing Applicationinitial access85 % - Secondary impact
T1078Valid Accountsstealth · persistence · privilege escalation · initial access80 %
AV:N/PR:N/UI:N permite explotación remota sin privilegios (T1190). UNIQUE_ID es predecible (IP pública, PID y timestamp adivinables), permitiendo forjar IDs de sesión y secuestrar sesiones de usuario.
Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.
🛡️ ATT&CK mitigations that cover these techniques
Affected technologies (1)
CWEs
- CWE-340
- CWE-341
References
- https://httpd.apache.org/docs/current/mod/mod_unique_id.html
- https://metacpan.org/pod/Apache::Session::Generate::Random
- http://www.openwall.com/lists/oss-security/2026/05/06/6
- https://access.redhat.com/security/cve/CVE-2026-5081
- https://bugzilla.redhat.com/show_bug.cgi?id=2467174
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5081.json
Raw JSON (NVD)
Show
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