CVE-2026-13503
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidencePath traversal vulnerability in ANTLR4's tokenVocab Grammar Option Handler allows remote attackers to access files outside the expected vocabulary directory via the getImportedVocabFile function in TokenVocabParser.java. The manipulation of the tokenVocab parameter enables reading or writing files to arbitrary locations on the filesystem.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Locate ANTLR4 installationSearch for antlr4-*.jar files, or check package managers (Maven, pip, npm) for antlr4 dependencies in project dependency files (pom.xml, package.json, requirements.txt).Affected if ANTLR4 library is found in the environment
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Identify ANTLR4 versionCheck the jar filename, Maven dependency version, or run 'java -jar antlr4-version.jar' with --version. Compare against 4.13.2.Affected if Version is 4.13.2 or lower, or the version cannot be determined (unknown versions)
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Find grammar files using tokenVocabSearch project directories for .g4 grammar files containing the 'tokenVocab' option: grep -r 'tokenVocab' *.g4Affected if Grammar files reference tokenVocab option pointing to vocabulary files
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Inspect tokenVocab paths for traversalExamine tokenVocab values in grammar files for path traversal patterns such as '../', absolute paths (/), or unusual directory references outside expected vocab directories.Affected if tokenVocab values contain '../', absolute paths, or point outside the expected vocabulary directory
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Monitor file access via TokenVocabParserIf ANTLR4 is used programmatically, audit code that invokes TokenVocabParser or getImportedVocabFile to verify path validation is performed before passing tokenVocab parameters.Affected if Application parses tokenVocab without validating or canonicalizing the path first
If ANTLR4 version is 4.13.2 or lower and grammar files or code use tokenVocab with unvalidated paths, the environment is vulnerable to CVE-2026-13503 path traversal.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade to patched ANTLR4 version beyond 4.13.2 when available; implement strict input validation and canonicalization on the tokenVocab parameter to restrict file paths to expected directories; apply principle of least privilege to file system access.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-13503 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-13503 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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