thClaws up to 0.141.0 post_inputs /v1/inputs symlink

Summaryinfo

A vulnerability classified as problematic has been found in thClaws up to 0.141.0. This impacts an unknown function of the file /v1/inputs of the component post_inputs. Performing a manipulation results in symlink. This vulnerability is reported as CVE-2026-108839. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as problematic, was found in thClaws up to 0.141.0. This affects some unknown processing of the file /v1/inputs of the component post_inputs. The manipulation with an unknown input leads to a symlink vulnerability. CWE is classifying the issue as CWE-61. The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files. This is going to have an impact on integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at hackmd.io. This vulnerability is uniquely identified as CVE-2026-108839 since 10/11/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/11/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• thClaws

Version

• 0.141

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

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