CVE-2026-67435 linuxfabrik-lib: fetch() forwards credential headers across a cross-origin redirect
Attackers can steal sensitive authentication headers from monitoring requests by exploiting cross-origin redirects in the fetch function.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-67435?
CVE-2026-67435 is a medium-severity server-side request forgery vulnerability in Linuxfabrik monitoring-plugins, published on 29 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
linuxfabrik-lib provides Python modules for database access, caching, shell execution, and API integrations. Prior to version 6.0.0, lib.url.fetch() followed cross-origin redirects while forwarding caller-supplied credential headers other than Authorization and Cookie, allowing a malicious redirect-capable server to receive headers such as X-Auth-Token from authenticated monitoring requests. This issue is fixed in version 6.0.0.
Which versions are affected by CVE-2026-67435?
3 open source packages ship an affected version, including linuxfabrik-lib.
| Package | Affected | Fixed in |
|---|---|---|
linuxfabrik-lib PyPI | All versions | 6.0.0 |
linuxfabrik-lib PyPI | All versions | 6.0.0 |
linuxfabrik-lib PyPI | All versions | 6.0.0 |
How do I fix CVE-2026-67435?
Upgrade linuxfabrik-lib to 6.0.0 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-67435 being exploited?
There is no known exploitation of CVE-2026-67435 in the wild and no public exploit code.
Sources
Also known as GHSA-4jc5-g844-4x33, PYSEC-2026-3578.