CVE-2026-39825
Description
ReverseProxy can forward queries containing parameters not visible to Rewrite functions. When used with a Rewrite function, or a Director function which parses query parameters, ReverseProxy sanitizes the forwarded request to remove query parameters which are not parsed by url.ParseQuery. ReverseProxy does not take ParseQuery's limit on the total number of query parameters (controlled by GODEBUG=urlmaxqueryparams=N) into account. This can permit ReverseProxy to forward a request containing a query parameter that is not visible to the Rewrite function. For example, the query "a1=x&a2=x&...&a10000=x&hidden=y" can forward the parameter "hidden=y" while hiding it from the proxy's Rewrite function.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Windows Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Affected | — |
| sid | Fixed | 1.25.10-1 |
| forky | Fixed | 1.25.10-1 |
| bullseye | Affected | — |
| bookworm | Affected | — |
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| Go | stdlib | >=1.26.0-0,<1.26.3 | 1.25.10 |
References
- https://go.dev/cl/770541
- https://go.dev/issue/78948
- https://groups.google.com/g/golang-announce/c/qcCIEXso47M
- https://pkg.go.dev/vuln/GO-2026-4976
- https://security-tracker.debian.org/tracker/CVE-2026-39825
- https://www.suse.com/security/cve/CVE-2026-39825.html
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-39825
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.