HTTP::Session2 versions before 1.12 for Perl may generate weak session ids using the rand() function
Published Feb 27, 2026
6.5
MEDIUMCVSS 3.1
EPSS 0.49%
Description
HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the rand() function.
The HTTP::Session2 session id generator returns a SHA-1 hash seeded with the built-in rand function, the epoch time, and the PID. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand() function is unsuitable for cryptographic usage.
HTTP::Session2 after version 1.02 will attempt to use the /dev/urandom device to generate a session id, but if the device is unavailable (for example, under Windows), then it will revert to the insecure method described above.
Affected products
-
- Version 0StatusaffectedConstraints<1.12
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Tokuhirom | n/a | unaffected |
|
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
Vendor solution
HTTP::Session2 has been deprecated since version 1.11. Migrate to a different solution.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
YesTechnical Impact
PartialDecision
n/aAssessed Mar 3, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 3, 2026.
Score over time
Feb–Oct 2026- EPSS v4
- EPSS v5
Percentile over time
- EPSS v4
- EPSS v5
Table of values (3 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 3, 2026 | 0.49% (0.00490) | 39.97th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.42% (0.00418) | 33.18th | v5 (v2026.06.15) |
| Feb 28, 2026 | 0.01% (0.00006) | 0.31th | v4 (v2025.03.14) |
References (5)
- http://www.openwall.com/lists/oss-security/2026/02/27/12 Mailing ListThird Party Advisory
- https://github.com/tokuhirom/HTTP-Session2/commit/9cfde4d7e0965172aef5dcfa3b03bb48df93e636.patch patch
- https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.01/source/lib/HTTP/Session2/ServerStore.pm#L68 Issue Tracking
- https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.11/source/lib/HTTP/Session2/Random.pm#L35 Issue Tracking
- https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.12/changes release-notesRelease Notes
| Link | Providers | Tags |
|---|---|---|
| http://www.openwall.com/lists/oss-security/2026/02/27/12 | Mailing ListThird Party Advisory | |
| https://github.com/tokuhirom/HTTP-Session2/commit/9cfde4d7e0965172aef5dcfa3b03bb48df93e636.patch | patch | |
| https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.01/source/lib/HTTP/Session2/ServerStore.pm#L68 | Issue Tracking | |
| https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.11/source/lib/HTTP/Session2/Random.pm#L35 | Issue Tracking | |
| https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.12/changes | release-notesRelease Notes |
Change history (0)
No recorded changes yet.