CVE-2026-13500
HighCVSS 7.3Exploitation Probability (EPSS)
Low risk23th percentile — higher than 23% of all known CVEs
Summary
A vulnerability has been found in ANTLR4 up to version 4.13.2 in the grammar action block handler function within OutputFile.java. Input manipulation can lead to remote code injection. A public exploit is available for attacks.
Risk Assessment
The organization is at risk of remote code execution via injection of malicious code into applications using the vulnerable ANTLR4 version. This could compromise data confidentiality, integrity, and availability.
Recommendation
Immediately update ANTLR4 to a version newer than 4.13.2 if available, or apply temporary mitigations such as input validation for data processed by the grammar.
Original NVD description (English source)
A weakness has been identified in antlr ANTLR4 up to 4.13.2. Affected is an unknown function of the file tool/src/org/antlr/v4/codegen/model/OutputFile.java of the component Grammar Action Block Handler. Executing a manipulation can lead to code injection. The attack may be launched remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.