CVE-2026-3256: CWE-340 Generation of Predictable Numbers or Identifiers in KTAT HTTP::Session
HTTP::Session versions before 0.54 for Perl defaults to using insecurely generated session ids. HTTP::Session defaults to using HTTP::Session::ID::SHA1 to generate session ids using a SHA-1 hash seeded with the built-in rand function, the high resolution 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. The distribution includes HTTP::session::ID::MD5 which contains a similar flaw, but uses the MD5 hash instead.
AI Analysis
Technical Summary
HTTP::Session versions prior to 0.54 generate session IDs using HTTP::Session::ID::SHA1, which seeds a SHA-1 hash with the built-in rand function, high resolution epoch time, and PID. The built-in rand function is not cryptographically secure, the PID is from a small set of values, and the epoch time can be guessed or leaked, making session IDs predictable. A similar flaw exists in HTTP::Session::ID::MD5, which uses MD5 hashing with the same weak seed sources. This vulnerability is classified under CWE-340 (Generation of Predictable Numbers or Identifiers) and CWE-338 (Use of Cryptographically Weak Pseudo-Random Number Generator).
Potential Impact
Predictable session IDs can allow attackers to guess or forge valid session identifiers, potentially leading to session hijacking and unauthorized access. The vulnerability affects confidentiality, integrity, and availability as indicated by the CVSS score of 9.8 (critical).
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should avoid using affected versions and consider implementing alternative secure session ID generation methods that use cryptographically secure random number generators.
CVE-2026-3256: CWE-340 Generation of Predictable Numbers or Identifiers in KTAT HTTP::Session
Description
HTTP::Session versions before 0.54 for Perl defaults to using insecurely generated session ids. HTTP::Session defaults to using HTTP::Session::ID::SHA1 to generate session ids using a SHA-1 hash seeded with the built-in rand function, the high resolution 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. The distribution includes HTTP::session::ID::MD5 which contains a similar flaw, but uses the MD5 hash instead.
CVSS v3.1
Score 9.8critical
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
HTTP::Session versions prior to 0.54 generate session IDs using HTTP::Session::ID::SHA1, which seeds a SHA-1 hash with the built-in rand function, high resolution epoch time, and PID. The built-in rand function is not cryptographically secure, the PID is from a small set of values, and the epoch time can be guessed or leaked, making session IDs predictable. A similar flaw exists in HTTP::Session::ID::MD5, which uses MD5 hashing with the same weak seed sources. This vulnerability is classified under CWE-340 (Generation of Predictable Numbers or Identifiers) and CWE-338 (Use of Cryptographically Weak Pseudo-Random Number Generator).
Potential Impact
Predictable session IDs can allow attackers to guess or forge valid session identifiers, potentially leading to session hijacking and unauthorized access. The vulnerability affects confidentiality, integrity, and availability as indicated by the CVSS score of 9.8 (critical).
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should avoid using affected versions and consider implementing alternative secure session ID generation methods that use cryptographically secure random number generators.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- CPANSec
- Date Reserved
- 2026-02-26T11:59:23.755Z
- Cvss Version
- null
- State
- PUBLISHED
Threat ID: 69c826972b68dbd88eafb4bf
Added to database: 03/28/2026, 19:05:59 UTC
Last enriched: 06/29/2026, 21:08:49 UTC
Last updated: 07/28/2026, 08:52:01 UTC
Views: 160
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.