dbcve.org
Amon2Application · Tokuhirom

CVE-2025-15604

CRITICAL · 9.8 CVSS v3.1 Published 2026-03-28
Fix available
A fix is available. Upgrade to 6.17 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Amon2 Perl framework's random_string() function uses a cryptographically weak fallback when /dev/urandom is unavailable, generating session IDs, cookie secrets, and CSRF tokens using a SHA-1 hash seeded with the predictable built-in rand() function, PID (small set), and guessable epoch time (potentially leaked from HTTP Date headers). This makes security tokens predictable and exploitable for session hijacking or CSRF attacks.

MitigationUpgrade Amon2 to version 6.17 or later which implements a cryptographically secure random_string function. Review and regenerate any existing session IDs, cookie secrets, and CSRF tokens that may have been generated with vulnerable versions.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Amon2Application
Affected:< 6.17

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Amon2 version
    Run 'perl -MAmon2 -e 'print Amon2->VERSION'' or check your cpanfile/cpanfile.snapshot for 'Tokuhirom::Amon2' version
    Affected if Version is lower than 6.17 (e.g., 6.16, 6.15, etc.)
  2. Check if /dev/urandom is available
    Run 'test -r /dev/urandom && echo Available || echo Unavailable' on the server where the application runs
    Affected if /dev/urandom is unavailable or unreadable by the web server process - only then does the weak fallback code path execute
  3. Identify applications using Amon2
    Search project files for 'use Amon2' or 'use Amon2::Web' statements in Perl source files, or check for Amon2 in application dependency lists
    Affected if Your application imports or inherits from Amon2 modules
  4. Check if random_string is used for security tokens
    Search source code for calls to 'random_string' that generate session IDs, cookie secrets, or CSRF tokens - examine templates and controller logic for $c->random_string or $c->get_csrf_token patterns
    Affected if Your application calls random_string() to generate session identifiers, authentication cookies, or CSRF tokens without an external secure random source
  5. Check token generation configuration
    Inspect your Amon2 application configuration files for session or security settings, and look for custom random_string implementations that may override the default
    Affected if Tokens are generated using Amon2's built-in random_string without a custom secure override

Your environment is affected if you run any Amon2 version below 6.17 AND your application uses random_string() to generate session IDs, cookie secrets, or CSRF tokens on a system where /dev/urandom is unavailable.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.17 or later
Fixed in 6.17
Vendor patch github.com →
Interim mitigation

Upgrade Amon2 to version 6.17 or later which implements a cryptographically secure random_string function. Review and regenerate any existing session IDs, cookie secrets, and CSRF tokens that may have been generated with vulnerable versions.

Recommended fix High confidence

Amon2 version 6.17 or later

  1. Check current installed version of Amon2 (e.g., `cpan -D Amon2` or inspect your cpanfile)
  2. Upgrade to version 6.17 or later using your Perl package manager (e.g., `cpanm [email protected]` or `cpanupgrade Amon2`)
  3. Verify the upgrade was successful by checking the installed version
  4. Review your application code that uses random_string() for session IDs, cookie secrets, or CSRF tokens to ensure they are now using cryptographically secure random values

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Amon2 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-15604 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data