CVE-2026-13500: antlr ANTLR4 Grammar Action Block OutputFile.java code injection

Severity: high (CVSS 7.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-28 · updated 2026-10-25
Weakness: CWE-74

Description

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.

Affected products

ANTLR4: 4.13.0, 4.13.1, 4.13.2

References

https://github.com/wooyun123/wooyun/issues/4
https://vuldb.com/cve/CVE-2026-13500
https://vuldb.com/submit/838568
https://vuldb.com/vuln/374495
https://vuldb.com/vuln/374495/cti

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