# CVE-2026-108839: thClaws through 0.141.0 Symlink Following File Write via POST /v1/inputs

> Attackers can exploit symlink following in the API to write or truncate files outside the workspace with daemon privileges.

- **Severity:** Low 2.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 11 Oct 2026
- **Updated:** 18 Oct 2026
- **Also known as:** GHSA-8c39-3r7m-gwc4

## What is CVE-2026-108839?

CVE-2026-108839 is a low-severity path traversal vulnerability in thClaws, published on 11 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

thClaws through 0.141.0 contains a link-following vulnerability in the post_inputs handler of the v1 API POST /v1/inputs endpoint that allows writes outside the workspace by following symlinks. Attackers who plant a symlink under the allowed inputs/ prefix can cause later authenticated uploads to write or truncate files outside the workspace with daemon privileges.

Weakness: CWE-59 (Improper Link Resolution Before File Access)

## Which versions are affected by CVE-2026-108839?


## How do I fix CVE-2026-108839?

No fix has been published for CVE-2026-108839 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-108839 being exploited?

There is no known exploitation of CVE-2026-108839 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-108839 and fix it if it is affected.

What it is: CVE-2026-108839 is a low-severity path traversal vulnerability in thClaws, published on 11 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-108839 in the wild and no public exploit code.

Affected product: thClaws. 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-2026-108839/ (Markdown: https://insights.sbomify.com/CVE-2026-108839/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-108839
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-108839
- OSV: https://osv.dev/vulnerability/CVE-2026-108839

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-108839/
Summaries are generated and may contain mistakes; the official description above is the record.