CPANSA-HTTP-Session2-2026-3255: HTTP-Session2 vulnerability
| Publisher | giterlizzi | Document category | csaf_security_advisory |
|---|---|---|---|
| Initial release date | 2026-02-27T00:00:00 | Engine | CSAF Perl Toolkit 0.26 |
| Current release date | 2026-02-27T00:00:00 | Build Date | |
| Current version | 1 | Status | final |
| CVSS v3.1 Base Score | 6.5 | Severity | |
| Original language | Language | en | |
| Also referred to | |||
Vulnerability 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.
Vulnerabilities
CVE-2026-3255
Vulnerability DescriptionHTTP::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.
| Weakness | CWE-338 : Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) |
|---|
Product status
Known affected
| Product | Score | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| HTTP-Session2 less than 1.12 |
|
Fixed
- HTTP-Session2 greater than or equal 1.12
giterlizzi
Namespace: https://github.com/giterlizzi/
gdt@cpan.org
References
- CPANSA-HTTP-Session2-2026-3255 JSON self
https://raw.githubusercontent.com/giterlizzi/perl-CPANSA-CSAF/develop/csaf/white/2026/cpansa-http-session2-2026-3255.json - https://github.com/tokuhirom/HTTP-Session2/commit/9cfde4d7e0965172aef5dcfa3b03bb48df93e636.patch external
https://github.com/tokuhirom/HTTP-Session2/commit/9cfde4d7e0965172aef5dcfa3b03bb48df93e636.patch - https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.01/source/lib/HTTP/Session2/ServerStore.pm#L68 external
https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.01/source/lib/HTTP/Session2/ServerStore.pm#L68 - https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.11/source/lib/HTTP/Session2/Random.pm#L35 external
https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.11/source/lib/HTTP/Session2/Random.pm#L35 - https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.12/changes external
https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.12/changes - http://www.openwall.com/lists/oss-security/2026/02/27/12 external
http://www.openwall.com/lists/oss-security/2026/02/27/12 - CVE-2026-3255 (NVD) external
https://nvd.nist.gov/vuln/detail/CVE-2026-3255
Revision history
| Version | Date of the revision | Summary of the revision |
|---|---|---|
| 1 | Fri Feb 27 00:00:00 2026 | First release |
Sharing rules
TLP:WHITE
For the TLP version see: https://www.first.org/tlp/