CVE-2026-13573 in llvm-project
Summary
by MITRE • 06/29/2026
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 project was informed of the problem early through an issue report but has not responded yet.
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Analysis
by VulDB Data Team • 07/07/2026
The vulnerability identified in the llvm-project repository represents a critical stack-based buffer overflow within the llvm::StringMap::insert function located in the ValueSymbolTable module at /lib/IR/ValueSymbolTable.cpp. This flaw exists in versions up to 22.1.6 and demonstrates a fundamental memory safety issue that could be exploited by local attackers who possess sufficient privileges to execute code on the affected system. The buffer overflow occurs during the insertion of string map entries, where improper bounds checking allows malicious input to overwrite adjacent stack memory regions.
The technical implementation of this vulnerability stems from inadequate input validation within the StringMap data structure's insertion mechanism. When processing string key-value pairs, the function fails to properly verify the size of incoming data against allocated buffer boundaries, creating an exploitable condition that can be leveraged to execute arbitrary code through stack corruption. The attack vector requires local system access, meaning that exploitation cannot occur remotely but rather demands physical or authenticated access to the target machine. This characteristic limits the initial attack surface compared to remote exploits but still presents a significant security risk for systems where local privileges are compromised.
The operational impact of this vulnerability extends beyond simple privilege escalation as it could enable attackers to manipulate compiler behavior, potentially leading to code injection during compilation processes or undermining the integrity of compiled binaries. Attackers who successfully exploit this flaw could corrupt stack memory, redirect program execution flow, and potentially achieve arbitrary code execution with the privileges of the compromised process. The fact that a public exploit has been developed further amplifies the risk, as it eliminates the need for advanced exploitation techniques and makes this vulnerability accessible to threat actors with basic technical capabilities.
Security practitioners should immediately prioritize patching affected systems to address this vulnerability, as the lack of response from the project maintainers following the initial issue report indicates potential delays in remediation. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which specifically addresses buffer overflows occurring in stack memory regions and represents one of the most common classes of memory corruption vulnerabilities in software systems. Organizations should implement additional monitoring and input validation measures to detect potential exploitation attempts while preparing for the mandatory update cycle. The ATT&CK framework categorizes this type of vulnerability under the T1059.001 technique for Command and Scripting Interpreter, as attackers could leverage compromised compiler environments to execute malicious code during build processes, potentially creating persistent backdoors through modified source code compilation.
Mitigation strategies should include immediate deployment of patches from the llvm-project maintainers, implementation of stack canary protections where possible, and enhanced input validation at multiple layers of the software stack. System administrators should also consider restricting local system access to reduce the attack surface and implement runtime monitoring solutions capable of detecting anomalous memory access patterns that could indicate exploitation attempts. The vulnerability's presence in a widely-used compiler infrastructure means that organizations with extensive llvm-based development environments may face widespread impact, making prompt remediation essential for maintaining overall system security posture.