RCE in Antlr Antlr4
CVE-2026-13500
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.005 (41.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 41.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Antlr Antlr4 — versions 4.13.0, 4.13.1, 4.13.2
Weakness classification (CWE)
References
- vuldb.com/vuln/374495 (vdb-entry)
- vuldb.com/vuln/374495/cti (signature, permissions-required)
- vuldb.com/cve/CVE-2026-13500 (third-party-advisory)
- vuldb.com/submit/838568 (third-party-advisory)
- github.com/wooyun123/wooyun/issues/4 (issue-tracking, exploit)
Frequently asked questions
- What is CVE-2026-13500?
- CVE-2026-13500 is a high-severity vulnerability in Antlr Antlr4, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 7.3/10. Published 2026-06-28.
- How severe is CVE-2026-13500?
- High severity. CVSS v3 base score is 7.3 out of 10.