# CVE-2025-15604: Amon2 versions before 6.17 for Perl use an insecure random_string implementation for security functions

> Insecure random number generation in Amon2 allows attackers to predict session IDs and CSRF tokens, potentially leading to account takeover.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Mar 2026
- **Updated:** 1 Apr 2026
- **Also known as:** GHSA-7r2j-hgh9-jqqx

## What is CVE-2025-15604?

CVE-2025-15604 is a critical vulnerability in TOKUHIROM Amon2, published on 28 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

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

## Which versions are affected by CVE-2025-15604?

It affects 1 product.


Products: Tokuhirom Amon2.

## How do I fix CVE-2025-15604?

No fix has been published for CVE-2025-15604 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-15604 being exploited?

There is no known exploitation of CVE-2025-15604 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-15604 and fix it if it is affected.

What it is: CVE-2025-15604 is a critical vulnerability in TOKUHIROM Amon2, published on 28 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-15604 in the wild and no public exploit code.

Affected product: TOKUHIROM Amon2. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-15604/ (Markdown: https://insights.sbomify.com/CVE-2025-15604/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-15604
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-15604
- OSV: https://osv.dev/vulnerability/CVE-2025-15604

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-15604/
Summaries are generated and may contain mistakes; the official description above is the record.