# CVE-2026-22903: Stack Overflow via SESSIONID Cookie in lighttpd

> An unauthenticated attacker can cause a stack overflow via a long SESSIONID cookie, leading to crashes or potential remote code execution.

- **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:** 9 Feb 2026
- **Updated:** 9 Feb 2026
- **Also known as:** GHSA-23jw-jg3f-6352

## What is CVE-2026-22903?

CVE-2026-22903 is a critical memory corruption vulnerability in WAGO 0852-1322, published on 9 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An unauthenticated remote attacker can send a crafted HTTP request containing an overly long SESSIONID cookie. This can trigger a stack buffer overflow in the modified lighttpd server, causing it to crash and potentially enabling remote code execution due to missing stack protections.

Weakness: CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2026-22903?


## How do I fix CVE-2026-22903?

No fix has been published for CVE-2026-22903 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-22903 being exploited?

There is no known exploitation of CVE-2026-22903 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22903 and fix it if it is affected.

What it is: CVE-2026-22903 is a critical memory corruption vulnerability in WAGO 0852-1322, published on 9 Feb 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-2026-22903 in the wild and no public exploit code.

Affected product: WAGO 0852-1322. 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-2026-22903/ (Markdown: https://insights.sbomify.com/CVE-2026-22903/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22903
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22903
- OSV: https://osv.dev/vulnerability/CVE-2026-22903

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-22903/
Summaries are generated and may contain mistakes; the official description above is the record.