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Amon2\Application · Tokuhirom

CVE-2026-5082

MEDIUM · 5.3 CVSS v3.1 Published 2026-04-08
Fix available
A fix is available. Upgrade to after 7.03 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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::Plugin::Web::CSRFDefender versions from 7.00 through 7.03 for Perl generate an insecure session id. The generate_session_id function will attempt to read bytes from the /dev/urandom device, but if that is unavailable then it generates bytes using 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. Amon2::Plugin::Web::CSRFDefender versions before 7.00 were part of Amon2, which was vulnerable to insecure session ids due to CVE-2025-15604. Note that the author has deprecated this module.

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

Amon2::Plugin::Web::CSRFDefender versions 7.00-7.03 have a weak session ID generation function that falls back to insecure methods when /dev/urandom is unavailable. The fallback uses SHA-1 hashing of the built-in rand() function (not cryptographically secure), a small-set PID, and guessable epoch time. The epoch time may also be leaked via HTTP Date headers.

MitigationMigrate to an actively maintained session management solution, as the module is deprecated. If continued use is required, ensure /dev/urandom is always available and replace the fallback with a proper cryptographically secure random number generator.

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
Amon2\Application
Affected:>= 7.00, <= 7.03

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
None
Integrity
None
Availability
Low

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

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. Verify Amon2::Plugin::Web::CSRFDefender version
    Run 'perl -MAmon2::Plugin::Web::CSRFDefender -e "print $Amon2::Plugin::Web::CSRFDefender::VERSION"' or check your cpanfile/cpanfile.snapshot for the installed version
    Affected if version is 7.00, 7.01, 7.02, or 7.03
  2. Confirm /dev/urandom availability
    Run 'test -r /dev/urandom && echo "available" || echo "unavailable"' on the host running the Perl application
    Affected if the output is 'unavailable' - this triggers the insecure fallback path
  3. Check if CSRFDefender plugin is loaded
    Search your Amon2 application code (typically in lib/*/Web.pm or similar) for 'plugin "Web::CSRFDefender"' or 'enable "Web::CSRFDefender"'
    Affected if the plugin is loaded in your application configuration
  4. Verify session ID generation source
    Inspect the Amon2::Plugin::Web::CSRFDefender module code around session ID generation (typically in _session_id or similar methods) to see if it checks for /dev/urandom and falls back to rand()
    Affected if the code contains a fallback to rand() when /dev/urandom is missing

You are affected if you have version 7.00-7.03 installed, the CSRFDefender plugin is loaded in your application, and /dev/urandom is unavailable on your system, causing predictable session IDs to be generated.

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 a release after 7.03
Interim mitigation

Migrate to an actively maintained session management solution, as the module is deprecated. If continued use is required, ensure /dev/urandom is always available and replace the fallback with a proper cryptographically secure random number generator.

Recommended fix Moderate confidence
  1. This module (Amon2::Plugin::Web::CSRFDefender) has been deprecated by its author and no fixed version is mentioned in the available reference material.
  2. Consult the upstream project or community for guidance on migration to an alternative session management solution.
  3. Consider migrating to a different web framework with maintained session/CSRF protections if continued development is needed.
Caveat The module is deprecated with no available upgrade path

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

Fix this in Amon2\ Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,780
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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-2026-5082 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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