CVE-2026-32811 Heimdall: Path received via Envoy gRPC corrupted when containing query string
Attackers can bypass access control rules in Heimdall by exploiting URL encoding issues, potentially gaining unauthorized access if insecure defaults are enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-32811?
CVE-2026-32811 is a high-severity authentication bypass vulnerability in dadrus heimdall, published on 20 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. When using Heimdall in envoy gRPC decision API mode with versions 0.7.0-alpha through 0.17.10, wrong encoding of the query URL string allows rules with non-wildcard path expressions to be bypassed. Envoy splits the requested URL into parts, and sends the parts individually to Heimdall. Although query and path are present in the API, the query field is documented to be always empty and the URL query is included in the path field. The implementation uses go's url library to reconstruct the url which automatically encodes special characters in the path. As a consequence, a parameter like /mypath?foo=bar to Path is escaped into /mypath%3Ffoo=bar. Subsequently, a rule matching /mypath no longer matches and is bypassed. The issue can only lead to unintended access if Heimdall is configured with an "allow all" default rule. Since v0.16.0, Heimdall enforces secure defaults and refuses to start with such a configuration unless this enforcement is explicitly disabled, e.g. via --insecure-skip-secure-default-rule-enforcement or the broader --insecure flag. This issue has been fixed in version 0.17.11.
Which versions are affected by CVE-2026-32811?
3 open source packages ship an affected version, including github.com/dadrus/heimdall. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/dadrus/heimdall Go | From 0.7.0-alpha | 0.17.11 |
github.com/dadrus/heimdall Go | From 0.7.0-alpha | 0.17.11 |
github.com/dadrus/heimdall Go | From 0.7.0-alpha | 0.17.11 |
Products include Dadrus Heimdall.
How do I fix CVE-2026-32811?
Upgrade github.com/dadrus/heimdall to 0.17.11 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-32811 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32811 exists.
Sources
Also known as GHSA-r8x2-fhmf-6mxp, GO-2026-4742.