CVE-2025-15604

Published Mar 28, 2026

Last updated a month ago

Perl

Amon2

Overview

AI description

Automated description summarized from trusted sources.

CVE-2025-15604 identifies a cryptographic weakness within the `random_string` function of the Perl web framework Amon2, affecting versions prior to 6.17. The vulnerability stems from the use of predictable random number generation methods when the preferred entropy source, `/dev/urandom`, is unavailable. Specifically, Amon2 versions 6.06 through 6.16 attempt to read from `/dev/urandom`, but if it's not accessible, they fall back to generating bytes by concatenating a SHA-1 hash seeded with the built-in Perl `rand()` function, the process ID (PID), and the high-resolution epoch time. This fallback mechanism utilizes elements that are considered predictable, potentially allowing attackers to guess or reproduce tokens, which could lead to issues such as session hijacking, cookie forgery, or bypassing Cross-Site Request Forgery (CSRF) protections.

Description: Amon2 versions before 6.17 for Perl use an insecure random_string implementation for security functions. In versions 6.06 through 6.16, the random_string function will attempt to read bytes from the /dev/urandom device, but if that is unavailable then it generates bytes by concatenating a SHA-1 hash seeded with the built-in rand() function, the PID, and the high resolution epoch time. 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. Before version 6.06, there was no fallback when /dev/urandom was not available. Before version 6.04, the random_string function used the built-in rand() function to generate a mixed-case alphanumeric string. This function may be used for generating session ids, generating secrets for signing or encrypting cookie session data and generating tokens used for Cross Site Request Forgery (CSRF) protection.
Source: 9b29abf9-4ab0-4765-b253-1875cd9b441e
NVD status: Modified
Products: amon2

Risk scores

CVSS 3.1

Type: Primary
Base score: 9.8
Impact score: 5.9
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: CRITICAL

Weaknesses

9b29abf9-4ab0-4765-b253-1875cd9b441e: CWE-338

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:tokuhirom:amon2:*:*:*:*:*:perl:*:*",
            "matchCriteriaId": "0920218A-C374-46FB-A8C8-FC92ACFB73DB",
            "versionEndExcluding": "6.17",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  }
]

A heap buffer overflow vulnerability was discovered in Perl. Release branches 5.34, 5.36, 5.38 and 5.40 are affected, including development versions from 5.33.1 through 5.41.10. When there are non-ASCII bytes in the left-hand-side of the `tr` operator, `S_do_trans_invmap` can overflow the destination pointer `d`. $ perl -e '$_ = "\x{FF}" x 1000000; tr/\xFF/\x{100}/;' Segmentation fault (core dumped) It is believed that this vulnerability can enable Denial of Service and possibly Code Execution attacks on platforms that lack sufficient defenses.•CVE-2024-56406

References

Sources include official advisories and independent security research.