Code Injection Vulnerability in ANTLR4 by antlr
CVE-2026-13500

6.9MEDIUM

Key Information:

Vendor

Antlr

Status
Antlr4
Vendor
CVE Published:
28 June 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-13500?

A vulnerability has been discovered in ANTLR4, specifically within the Grammar Action Block Handler component. The weakness resides in an unspecified function of the OutputFile.java file, allowing for potential code injection through manipulated input. This flaw can be exploited remotely, and following its public disclosure, there has been no communication from the vendor regarding mitigation strategies.

Affected Version(s)

ANTLR4 4.13.0

ANTLR4 4.13.1

ANTLR4 4.13.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-13500 - Proof of Concept

References

https://vuldb.com/vuln/374495
vdb-entry
https://vuldb.com/vuln/374495/cti
signaturepermissions-required
https://vuldb.com/cve/CVE-2026-13500
third-party-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

jiazhou (VulDB User)
VulDB CNA Team
.