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.
- 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
- None listed
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
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.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-108839 being exploited?
There is no known exploitation of CVE-2026-108839 in the wild and no public exploit code.
Sources
Also known as GHSA-8c39-3r7m-gwc4.