CVE-2026-3256CRITICAL 9.8EPSS p40.6%

CVE-2026-3256CVE-2026-3256

Description

HTTP::Session versions through 0.53 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.

Scoring

CVSS 3.19.8 (CRITICAL)
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS0.53% probability of exploitation · percentile 40.6% · 2026-06-18T12:00:27Z
Published2026-03-28
Last modified2026-04-01

Underlying weaknesses· 2

CWE-338CWE-340

References

  1. https://metacpan.org/release/KTAT/http-session-0.53/source/lib/HTTP/Session/ID/MD5.pm
  2. https://metacpan.org/release/KTAT/http-session-0.53/source/lib/HTTP/Session/ID/SHA1.pm
  3. https://security.metacpan.org/docs/guides/random-data-for-security.html
  4. http://www.openwall.com/lists/oss-security/2026/03/28/5

2

TypeTargetConfidenceTier
WeaknessUse of Cryptographically Weak Pseudo-Random Number Generator (PRNG)cwe-3380%live
WeaknessGeneration of Predictable Numbers or Identifierscwe-3400%live

Related by meaning· 6

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Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.