CVE-2026-56016

MEDIUM
MEDIUM Priority: 0.03 BB Relevance: 62/100
Published: 2026-07-01 Modified: 2026-10-25 First seen: 2026-10-29 Status: active

Attack Surface

Network No Auth No Interaction Conf. Impact

CVSS Vector Breakdown

AV: Network
AC: High
PR: None
UI: None
S: Unchanged
C: High
I: None
A: None

Description

CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources. The generate_id method builds the session id from a MD5 digest of the process id, the epoch time, and the built-in rand() function. All three are predictable, low-entropy sources: the PID is drawn from a small range, the epoch time can be guessed or read from the HTTP Date header, and Perl's rand() is unsuitable for security purposes because it is predictable and reversible. An attacker who predicts a session id can impersonate the corresponding session and bypass authentication.

Weakness Classification (2)

Bug Bounty Relevance

62 / 100
✓ Network accessible
✓ No authentication
✓ No user interaction

CVSS Score

5.9 / 10.0 v3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS — Exploitation Probability

0.51%
Raw Score 0.005130
Percentile 43.7%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00513
2026-10-28
0.00513

Intelligence Sources

nvd ref →