CVE-2026-117608 in Assimp
Summary
by MITRE • 10/28/2026
Assimp through 6.0.5 contains an integer overflow vulnerability in MD2Importer::ValidateHeader() that allows attackers to bypass frame table bounds checks using crafted header fields. Attackers can supply a malicious .md2 file whose numFrames and numVertices values wrap the 32-bit size check, causing heap out-of-bounds reads that crash applications or expose adjacent heap memory.
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Analysis
by VulDB Data Team • 10/28/2026
The vulnerability identified in Assimp versions through 6.0.5 represents a critical security flaw within the MD2 model importer module, specifically located in the ValidateHeader function. This component is responsible for parsing and validating the structural integrity of .md2 files before they are processed further by the graphics engine or application utilizing the library. The core technical issue stems from an integer overflow condition that occurs during the validation of header fields, particularly numFrames and numVertices. These values define the dimensions of internal data structures such as frame tables and vertex arrays. When a malicious actor supplies a crafted .md2 file with specific numeric values for these headers, they can cause the arithmetic operations used to calculate buffer sizes or array bounds to wrap around due to 32-bit integer limitations. This wrapping effect allows the attacker to bypass critical size checks that are designed to prevent access beyond allocated memory boundaries.
From a technical perspective, this flaw is classified as CWE-190: Integer Overflow or Wraparound. The vulnerability arises because the validation logic fails to account for potential overflow scenarios when multiplying or adding values derived from untrusted input fields like numFrames and numVertices. Instead of rejecting files with suspiciously large calculated sizes that would indicate an overflow, the code proceeds with allocation or access operations based on the wrapped, smaller value. Consequently, subsequent read operations targeting these data structures exceed the bounds of the allocated heap memory. This leads to a CWE-125: Out-of-bounds Read vulnerability, where the application attempts to access memory locations that are not part of the intended buffer.
The operational impact of this vulnerability is severe and multifaceted. Primarily, it can lead to denial of service conditions as applications crash when attempting to read from invalid or unmapped memory addresses. However, beyond simple crashes, the out-of-bounds read poses a significant risk of information disclosure. By reading adjacent heap memory, an attacker may be able to extract sensitive data stored in neighboring allocations, such as cryptographic keys, session tokens, or other private user information. This capability transforms what might otherwise appear as a stability issue into a potential vector for remote code execution if combined with further exploitation techniques that leverage the leaked memory contents to manipulate control flow.
This vulnerability aligns with MITRE ATT&CK technique T1208: Weak Encryption Algorithm in some contexts where data leakage is exploited, but more accurately maps to T1567: Exfiltration Over Web Service or direct system exfiltration if the attacker can send the leaked memory contents out of band. It also relates to CWE-209: Generation of Error Message Containing Sensitive Information if the crash dumps are generated and accessible. The attack vector is typically remote, requiring only that a victim application loads a malicious .md2 file, which could be delivered via email attachments, compromised websites, or other means where user interaction triggers the loading process.
Mitigation strategies for this vulnerability involve both immediate patching and long-term defensive coding practices. Users of Assimp should immediately upgrade to version 6.0.6 or later, where the integer overflow in MD2Importer::ValidateHeader has been addressed with proper bounds checking that accounts for potential overflows before allocation or access occurs. For developers integrating Assimp into their applications, it is crucial to ensure that all third-party libraries are kept up to date with security patches. Additionally, implementing input validation at the application level can provide an additional layer of defense by sanitizing file inputs before they reach the parsing engine. Employing memory-safe languages or using static analysis tools during development can help identify similar integer overflow patterns in custom code, reducing the attack surface for future vulnerabilities.