CVE-2026-13503 antlr ANTLR4 tokenVocab Grammar Option TokenVocabParser.java getImportedVocabFile path traversal
Remote attackers can exploit a path traversal flaw in ANTLR4's tokenVocab handler to read arbitrary files from the system.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-13503?
CVE-2026-13503 is a medium-severity path traversal vulnerability in ANTLR4, published on 28 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability was detected in antlr ANTLR4 up to 4.13.2. Affected by this issue is the function getImportedVocabFile of the file tool/src/org/antlr/v4/parse/TokenVocabParser.java of the component tokenVocab Grammar Option Handler. The manipulation results in path traversal. The attack can be executed remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Weakness: CWE-22
Which versions are affected by CVE-2026-13503?
How do I fix CVE-2026-13503?
No fix published yet.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-13503 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-13503 exists.
Sources
Also known as CLSA-2026-1791472866, CLSA-2026-1791480304, CLSA-2026-1793128354, CLSA-2026-1793128545, DEBIAN-CVE-2026-13503, GHSA-w346-wxvq-p3xr and 2 more.