# CVE-2026-8503: Apache::Session::Generate::SHA256 versions before 1.3.19 for Perl create insecure session ids

> Insecure session ID generation using low-entropy sources allows attackers to predict IDs and hijack user sessions.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 May 2026
- **Updated:** 15 May 2026
- **Also known as:** DEBIAN-CVE-2026-8503, GHSA-2c59-fqg7-rwrx, UBUNTU-CVE-2026-8503

## What is CVE-2026-8503?

CVE-2026-8503 is a medium-severity vulnerability in GUIMARD Apache::Session::Generate::SHA256, published on 15 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Apache::Session::Generate::SHA256 versions before 1.3.19 for Perl create insecure session ids.

Apache::Session::Generate::SHA256 generated session ids insecurely. The default session id generator returns a SHA-256 hash of the built-in rand() function, the epoch time, and the PID, that is hashed again. These are predictable, low-entropy sources. Predicable session ids could allow an attacker to gain access to systems.

Note that version 1.3.19 has a fallback without warning to use insecure session generation method if the call to Crypt::URandom::urandom fails. However, this is unlikely as Crypt::URandom is a hardcoded requirement of the module.

This issue is similar to CVE-2025-40931 for Apache::Session::Generate::MD5.

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-2026-8503?

It affects 1 product.


Products: Guimard Apache\.

## How do I fix CVE-2026-8503?

Upgrade to a fixed version.

## Is CVE-2026-8503 being exploited?

There is no known exploitation of CVE-2026-8503 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8503 and fix it if it is affected.

What it is: CVE-2026-8503 is a medium-severity vulnerability in GUIMARD Apache::Session::Generate::SHA256, published on 15 May 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-2026-8503 in the wild and no public exploit code.

Affected product: GUIMARD Apache::Session::Generate::SHA256. 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-2026-8503/ (Markdown: https://insights.sbomify.com/CVE-2026-8503/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8503
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8503
- OSV: https://osv.dev/vulnerability/CVE-2026-8503

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-8503/
Summaries are generated and may contain mistakes; the official description above is the record.