CVE-2019-14973 in LibTIFF
Summary
by MITRE
_TIFFCheckMalloc and _TIFFCheckRealloc in tif_aux.c in LibTIFF through 4.0.10 mishandle Integer Overflow checks because they rely on compiler behavior that is undefined by the applicable C standards. This can, for example, lead to an application crash.
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Analysis
by VulDB Data Team • 05/16/2025
The vulnerability identified as CVE-2019-14973 resides within the LibTIFF library version 4.0.10 and earlier, specifically affecting the TIFFCheckMalloc and TIFFCheckRealloc functions located in the tif_aux.c source file. This issue represents a critical flaw in memory management operations that can lead to unpredictable application behavior and potential system instability. The root cause stems from the library's reliance on compiler-specific behavior that violates established C standard compliance, creating an environment where integer overflow checks fail to operate correctly. When applications process TIFF image files through LibTIFF, they become susceptible to memory corruption scenarios that can result in application crashes or more severe security implications.
The technical flaw manifests through undefined behavior in integer overflow detection mechanisms that are fundamental to memory allocation safety. These functions perform checks to prevent integer overflows during memory allocation operations, but they depend on compiler optimizations and behaviors that are not guaranteed by the C standard. When compilers perform certain optimizations or handle integer arithmetic in ways that differ from the standard's specifications, the overflow detection logic fails to properly identify potentially dangerous memory allocation scenarios. This creates a situation where maliciously crafted TIFF files could trigger integer underflow or overflow conditions that bypass normal safety checks, leading to memory corruption and application instability. The vulnerability falls under CWE-191, which specifically addresses integer underflow (wrap or wraparound) and CWE-190, which covers integer overflow and wraparound conditions.
The operational impact of this vulnerability extends beyond simple application crashes to encompass potential security risks in systems that process TIFF image files. Applications using LibTIFF for image processing, including document management systems, image viewers, and server applications handling user-uploaded content, become vulnerable to denial of service attacks. Attackers could craft specially formatted TIFF files that trigger the integer overflow conditions, causing applications to crash or behave unpredictably. The vulnerability is particularly concerning in server environments where applications might be processing untrusted TIFF content from external sources, as it could enable remote attackers to cause service disruption through carefully constructed image files. This aligns with ATT&CK technique T1499.001, which describes the use of resource exhaustion attacks through malformed file formats.
Mitigation strategies for CVE-2019-14973 require immediate attention from system administrators and software developers. The primary recommendation involves upgrading to LibTIFF version 4.0.11 or later, where the integer overflow handling has been corrected to comply with C standard requirements. Organizations should conduct thorough vulnerability assessments to identify all systems and applications that utilize affected versions of LibTIFF, particularly those handling untrusted image content. Additionally, implementing proper input validation and sanitization measures can provide defense-in-depth protection against exploitation attempts. Security teams should consider deploying network-based intrusion detection systems that can identify suspicious TIFF file patterns and monitor for potential exploitation attempts. The fix implemented in newer versions addresses the underlying undefined behavior by using more robust integer arithmetic checks that do not rely on compiler-specific optimizations, ensuring consistent behavior across different compilation environments and platforms.