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Fencer Vulns
medium 6.5

CVE-2026-5084 json

WebDyne::Session versions before 3.003_704 for Perl generate the session id insecurely

published 2026-05-11 5 mo ago modified 2026-10-26 13 d ago also EUVD-2026-29039

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 26%
public exploits
0
none known

Summary

WebDyne::Session versions before 3.003_704 for Perl generate the session id insecurely.

The session handler generates the session id from an MD5 hash seeded with a call to the built-in rand() function. The rand function is passed a maximum value based on the process id, the epoch time and the reference address of the object, but this information will have no effect on the overall quality of the seed of the message digest.

The rand function is seeded by 32-bits and is predictable. It is considered unsuitable for cryptographic purposes.

Predictable session ids could allow an attacker to gain access to systems.

Note that WebDyne::Session versions 1.042 and earlier appear to be in separate distributions from WebDyne.

Patch / fix

  • ASPEER WebDyne::Session 3.003_704

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-08).

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

  • ASPEER WebDyne::Session

Classification

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

References

Sources

Fencer Vulns 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.