CVE-2026-13500

A flaw was found in ANTLR4. A remote attacker could exploit a weakness within the Grammar Action Block Handler component by executing a manipulation. This vulnerability allows for code injection, which can lead to the execution of arbitrary code on the affected system.

This is an Important vulnerability. A remote code injection flaw exists in the ANTLR4 Grammar Action Block Handler, which could allow an unauthenticated attacker to execute arbitrary code. The ability for remote exploitation and the public availability of exploit details elevate the risk, making this a critical concern for Red Hat products that incorporate ANTLR4 and process untrusted input.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.