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CVE-2026-3255

HTTP::Session2 versions before 1.12 for Perl may generate weak session ids using the rand() function

Published: Feb 27, 2026Updated: Mar 4, 2026 Sources: CVE List NVDCWE-338
NVD MITRE
6.5CVSSMEDIUM
EPSS Score
0.4%
Top 66.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:LI:NA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:NIntegrity
None
A:LAvailability
Low
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Weaknesses

CWE-338CWE-340

Affected Products

http\tokuhirom
Library
OSS Libraries / generic-library
HTTP::Session2TOKUHIROM
Library
OSS Libraries / generic-library
tokuhiromindividual-devOSS Librariesaka tokuhirom tr y

Exploitability

Official Patch Available
Workaround Available

References

https://github.com/tokuhirom/HTTP-Session2/commit/9cfde4d7e0965172aef5dcfa3b03bb48df93e636.patch
github.com
https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.01/source/lib/HTTP/Session2/ServerStore.pm#L68
metacpan.org
https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.11/source/lib/HTTP/Session2/Random.pm#L35
metacpan.org
and 2 more references View all →

Timeline

Published
Feb 27, 2026
Last Updated
Mar 4, 2026

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