CPANSA-Amon2-2025-15604: Amon2 vulnerability
| Publisher | giterlizzi | Document category | csaf_security_advisory |
|---|---|---|---|
| Initial release date | 2026-03-28T00:00:00 | Engine | CSAF Perl Toolkit 0.26 |
| Current release date | 2026-03-28T00:00:00 | Build Date | |
| Current version | 1 | Status | final |
| CVSS v3.1 Base Score | 9.8 | Severity | |
| Original language | Language | en | |
| Also referred to | |||
Vulnerability 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.
Vulnerabilities
CVE-2025-15604
Vulnerability DescriptionAmon2 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.
| Weakness | CWE-338 : Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) |
|---|
Product status
Known affected
| Product | Score | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Amon2 less than 6.18 |
|
Fixed
- Amon2 greater than or equal 6.18
giterlizzi
Namespace: https://github.com/giterlizzi/
gdt@cpan.org
References
- CPANSA-Amon2-2025-15604 JSON self
https://raw.githubusercontent.com/giterlizzi/perl-CPANSA-CSAF/develop/csaf/white/2026/cpansa-amon2-2025-15604.json - https://github.com/tokuhirom/Amon/pull/135 external
https://github.com/tokuhirom/Amon/pull/135 - https://metacpan.org/release/TOKUHIROM/Amon2-6.17/changes external
https://metacpan.org/release/TOKUHIROM/Amon2-6.17/changes - https://metacpan.org/release/TOKUHIROM/Amon2-6.17/diff/TOKUHIROM/Amon2-6.16#lib/Amon2/Util.pm external
https://metacpan.org/release/TOKUHIROM/Amon2-6.17/diff/TOKUHIROM/Amon2-6.16#lib/Amon2/Util.pm - https://security.metacpan.org/docs/guides/random-data-for-security.html external
https://security.metacpan.org/docs/guides/random-data-for-security.html - http://www.openwall.com/lists/oss-security/2026/03/28/4 external
http://www.openwall.com/lists/oss-security/2026/03/28/4 - CVE-2025-15604 (NVD) external
https://nvd.nist.gov/vuln/detail/CVE-2025-15604
Revision history
| Version | Date of the revision | Summary of the revision |
|---|---|---|
| 1 | Sat Mar 28 00:00:00 2026 | First release |
Sharing rules
TLP:WHITE
For the TLP version see: https://www.first.org/tlp/