GHSA-4jc5-g844-4x33: linuxfabrik-lib: fetch() forwards credential headers across a cross-origin redirect
Summary
lib.url.fetch() follows HTTP redirects (follow_redirects=True). httpx strips only Authorization and Cookie when a redirect crosses the origin, so any other caller-supplied credential header (a session token such as Redfish's X-Auth-Token, an API key, ...) was still sent to the redirect target. A malicious or redirect-capable server can therefore answer an authenticated request with a 3xx to an attacker-chosen host and receive the credential (server-side request forgery + token disclosure). The pre-httpx urllib implementation was worse: it forwarded every header, including Authorization, across cross-host redirects.
Impact
Any plugin that authenticates to a host with a non-standard auth header and follows that host's redirects can be coerced into sending the credential, and an authenticated request, to another host the monitoring server can reach. The concrete case is the Redfish checks (X-Auth-Token), but the flaw is in the shared fetch() and affects every consumer.
Patches
Fixed in linuxfabrik-lib 6.0.0 (commit 6573ff9). On a cross-origin redirect (any scheme/host/port change other than a plain same-host HTTP-to-HTTPS upgrade) fetch() now keeps only benign transport headers and drops every other caller-supplied header, so credentials never follow a redirect to a different origin.
Details
Original advisory: https://github.com/advisories/GHSA-4jc5-g844-4x33
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-674350.29% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 21% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-67435 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
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