# CVE-2026-51884: Path traversal in n/a

> Attackers can write files to arbitrary server locations via malicious filenames in the temporary document upload endpoint, potentially leading to 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:** 1 Oct 2026
- **Updated:** 5 Oct 2026
- **Also known as:** GHSA-c869-r44m-5f4w

## What is CVE-2026-51884?

CVE-2026-51884 is a critical path traversal vulnerability in n/a, published on 1 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The /knowledge_base/upload_temp_docs temporary document upload endpoint in Langchain Chatchat 0.3.1 is vulnerable to path traversal. By crafting malicious filenames, an attacker can write files to arbitrary locations on the server, bypassing the intended restrictions on the temporary directory.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-51884?


## How do I fix CVE-2026-51884?

No fix has been published for CVE-2026-51884 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-51884 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-51884 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-51884 and fix it if it is affected.

What it is: CVE-2026-51884 is a critical path traversal vulnerability in n/a, published on 1 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-51884 exists.

Affected product: n/a. 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-2026-51884/ (Markdown: https://insights.sbomify.com/CVE-2026-51884/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-51884
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-51884
- OSV: https://osv.dev/vulnerability/CVE-2026-51884

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-51884/
Summaries are generated and may contain mistakes; the official description above is the record.