Interpretation Conflict Affecting github.com/dadrus/heimdall/internal/rules package, versions <0.17.14
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published4 May 2026
- disclosed25 Apr 2026
- creditUnknown
Introduced: 25 Apr 2026
CVE-2026-42273 Â (opens in a new tab)How to fix?
Upgrade github.com/dadrus/heimdall/internal/rules to version 0.17.14 or higher.
Overview
Affected versions of this package are vulnerable to Interpretation Conflict due to case-sensitive handling of the host matching process. An attacker can bypass access control policies by sending requests with hostnames that differ only in letter casing, potentially gaining unauthorized access or escalating privileges. This is only exploitable if the system is configured with an "allow all" default rule or if secure default rule enforcement is explicitly disabled.
Workaround
This vulnerability can be mitigated by normalizing request hosts to lowercase before processing, avoiding permissive default rules, defining regex host matches as case-insensitive, or validating the expected rule ID in issued JWTs.