CVE-2026-5081
Apache::Session::Generate::ModUniqueId versions from 1.54 through 1.94 for Perl session ids are insecure
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).
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
9.1
Apache::Session::Generate::ModUniqueId versions from 1.54 through 1.94 for Perl session ids are insecure
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).
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.
- Record
CVE-2026-5081- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-340, CWE-341
- Updated
- 2026-11-02
EUVDEUVD-2026-27823
9.1
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).
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.
- Record
EUVD-2026-27823- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-546v-xqjf-qgcr
9.1
Apache::Session::Generate::ModUniqueId versions from 1.54 through 1.94 for Perl session ids are...
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).
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.
- Record
GHSA-546v-xqjf-qgcr- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-340, CWE-341
- Updated
- 2026-11-02
NVD
9.1
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).
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.
- Record
CVE-2026-5081- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-340, CWE-341
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-5081
9.1
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). 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.
- Record
DEBIAN-CVE-2026-5081- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-5081
9.1
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). 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.
- Record
UBUNTU-CVE-2026-5081- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
libapache-session-perlDebian:12 |
All versions, plus listed versions 1.94-2 |
None known |
libapache-session-perlDebian:13 |
All versions, plus listed versions 1.94-2 |
None known |
libapache-session-perlDebian:14 |
All versions, plus listed versions 1.94-2 |
None known |
libapache-session-perlUbuntu:16.04:LTS |
All versions, plus listed versions 1.93-21.93-2ubuntu1 |
None known |
libapache-session-perlUbuntu:18.04:LTS |
All versions, plus listed versions 1.93-2ubuntu1 |
None known |
libapache-session-perlUbuntu:20.04:LTS |
All versions, plus listed versions 1.93-3 |
None known |
libapache-session-perlUbuntu:22.04:LTS |
All versions, plus listed versions 1.94-1 |
None known |
libapache-session-perlUbuntu:24.04:LTS |
All versions, plus listed versions 1.94-2 |
None known |
libapache-session-perlUbuntu:25.10 |
All versions, plus listed versions 1.94-2 |
None known |
libapache-session-perlUbuntu:26.10 |
All versions, plus listed versions 1.94-2 |
None known |
libapache-session-perlUbuntu:26.04:LTS |
All versions, plus listed versions 1.94-2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-5081 is a critical vulnerability (CVSS 9.1) in Chorny Apache::session::generate::moduniqueid, published May 6, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 23rd percentile. No source names a fixed version.
References
httpd.apache.org/docs/current/mod/mod_unique_id.html
metacpan.org/pod/Apache::Session::Generate::Random
openwall.com/lists/oss-security/2026/05/06/6
access.redhat.com/security/cve/CVE-2026-5081
bugzilla.redhat.com/show_bug.cgi?id=2467174
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5081.json