# CVE-2026-5082: Amon2::Plugin::Web::CSRFDefender versions from 7.00 through 7.03 for Perl generate an insecure session id

> Attackers can predict session IDs due to weak entropy sources, enabling CSRF protection bypass in Perl applications using this deprecated plugin.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Apr 2026
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-gr8m-rq4x-q7c8

## What is CVE-2026-5082?

CVE-2026-5082 is a medium-severity vulnerability in TOKUHIROM Amon2::Plugin::Web::CSRFDefender, published on 8 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

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-2026-5082?

It affects 1 product.


Products: Tokuhirom Amon2\.

## How do I fix CVE-2026-5082?

No fix has been published for CVE-2026-5082 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-5082 being exploited?

There is no known exploitation of CVE-2026-5082 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5082 and fix it if it is affected.

What it is: CVE-2026-5082 is a medium-severity vulnerability in TOKUHIROM Amon2::Plugin::Web::CSRFDefender, published on 8 Apr 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-2026-5082 in the wild and no public exploit code.

Affected product: TOKUHIROM Amon2::Plugin::Web::CSRFDefender. 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-2026-5082/ (Markdown: https://insights.sbomify.com/CVE-2026-5082/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5082
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5082
- OSV: https://osv.dev/vulnerability/CVE-2026-5082

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5082/
Summaries are generated and may contain mistakes; the official description above is the record.