Improper Validation of Unsafe Equivalence in Input Affecting github.com/dunglas/mercure/caddy package, versions <0.22.0
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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- published12 Apr 2026
- disclosed9 Apr 2026
- creditdunglas
Introduced: 9 Apr 2026
CVE-2026-39972 (opens in a new tab)How to fix?
Upgrade github.com/dunglas/mercure/caddy to version 0.22.0 or higher.
Overview
Affected versions of this package are vulnerable to Improper Validation of Unsafe Equivalence in Input via the TopicSelectorStore process. An attacker can access private updates intended for authorized subscribers or prevent delivery to legitimate recipients by poisoning the match result cache through crafted topic names or selectors.