CVE-2026-13573: llvm llvm-project ValueSymbolTable ValueSymbolTable.cpp insert stack-based overflow

Vulnerability summary

CVE-2026-13573 is a medium (CVSS 4.8) vulnerability in llvm llvm-project. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 6.7% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 29-06-2026
   PublishedVulnerability first disclosed.
2. 07-07-2026
   Last modifiedVulnerability information updated.

Description

A vulnerability was found in llvm llvm-project up to 22.1.6. This affects the function llvm::StringMap::insert in the library /lib/IR/ValueSymbolTable.cpp of the component ValueSymbolTable Module. The manipulation results in stack-based buffer overflow. Attacking locally is a requirement. The exploit has been made public and could be used. The presence of this vulnerability remains uncertain at this time. The LLVM project explains, that the reported behavior is outside its documented security scope and therefore not considered a security vulnerability.

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferThe product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.
• CWE-121Stack-based Buffer OverflowThe product writes past the end of a buffer that was allocated on the stack.