# CVE-2026-13500 — antlr ANTLR4

> As of 2026-06-29, CVE-2026-13500 is a HIGH-severity vulnerability in antlr ANTLR4, CVSS v3.1 7.3, EPSS 0.3% (22.7th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-13500 as of 2026-06-29; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-06-29

## What is 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.

The record classifies CVE-2026-13500 under weakness classes [CWE-94](https://intel.threadlinqs.com/cwe/CWE-94), [CWE-74](https://intel.threadlinqs.com/cwe/CWE-74). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 99 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.3 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R`)
- **CVSS v4.0 base score:** 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 22.7% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-06-28, last modified 2026-06-29

## Is CVE-2026-13500 being exploited?

It currently carries a trending score of 35 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **antlr**: ANTLR4

## How to fix CVE-2026-13500

No vendor patch reference has been recorded for CVE-2026-13500 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-13500

No threat campaign in the Threadlinqs corpus currently references CVE-2026-13500, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-06-30.

**Exploit and proof of concept**

- [github.com — exploit](https://github.com/wooyun123/wooyun/issues/4)

**Third-party advisory**

- [vuldb.com — signature](https://vuldb.com/vuln/374495/cti)
- [vuldb.com — third party advisory](https://vuldb.com/cve/CVE-2026-13500)
- [vuldb.com — third party advisory (838568)](https://vuldb.com/submit/838568)

**Vulnerability database entry**

- [vuldb.com — vdb entry](https://vuldb.com/vuln/374495)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-13500
Full detection coverage and IOCs for threats exploiting CVE-2026-13500 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp