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Fencer Intel
medium 6.5

CVE-2026-8503 json

Apache::Session::Generate::SHA256 versions before 1.3.19 for Perl create insecure session ids

published 5mo ago modified 16d ago also EUVD-2026-30536

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

Apache::Session::Generate::SHA256 versions before 1.3.19 for Perl create insecure session ids.

Apache::Session::Generate::SHA256 generated session ids insecurely. The default session id generator returns a SHA-256 hash of the built-in rand() function, the epoch time, and the PID, that is hashed again. These are predictable, low-entropy sources. Predicable session ids could allow an attacker to gain access to systems.

Note that version 1.3.19 has a fallback without warning to use insecure session generation method if the call to Crypt::URandom::urandom fails. However, this is unlikely as Crypt::URandom is a hardcoded requirement of the module.

This issue is similar to CVE-2025-40931 for Apache::Session::Generate::MD5.

Patch / fix

  • GUIMARD Apache::Session::Generate::SHA256 1.3.19
  • libapache-session-browseable-perl Debian 12 1.3.11-3+deb12u1
  • libapache-session-browseable-perl Debian 13 1.3.16-1+deb13u1
  • libapache-session-browseable-perl Debian 14 1.3.19-1

debian advisories DEBIAN-CVE-2026-8503

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-8503 updated cvss 7.4

perl-Apache-Session-Browseable: perl-Apache-Session-Browseable: Predictable session IDs allow unauthorized system access

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected products

  • GUIMARD Apache::Session::Generate::SHA256

Classification

Weakness
  • CWE-340 Generation of Predictable Numbers or Identifiers
  • CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.