CVE-2022-1623 in LibTIFF
Summary
by MITRE • 05/11/2022
LibTIFF master branch has an out-of-bounds read in LZWDecode in libtiff/tif_lzw.c:624, allowing attackers to cause a denial-of-service via a crafted tiff file. For users that compile libtiff from sources, the fix is available with commit b4e79bfa.
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Analysis
by VulDB Data Team • 04/09/2026
The vulnerability identified as CVE-2022-1623 represents a critical out-of-bounds read condition within the LibTIFF library's LZW decoding implementation. This flaw exists in the master branch of the library at line 624 within the file libtiff/tif_lzw.c, where the LZWDecode function fails to properly validate input data boundaries during decompression operations. The issue arises when processing crafted TIFF files that contain malformed LZW compressed data, creating a scenario where the decoder attempts to access memory locations beyond the allocated buffer boundaries. Such out-of-bounds memory access can lead to unpredictable behavior and system instability.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions that occur when a program accesses memory beyond the boundaries of a buffer. The flaw specifically manifests during the LZW decompression process where the decoder does not adequately verify the integrity of compressed data before attempting to read from it. This allows attackers to construct malicious TIFF files that, when processed by applications relying on LibTIFF, trigger the out-of-bounds read condition. The vulnerability is particularly concerning as it operates at the library level, meaning any application that utilizes LibTIFF for TIFF file processing becomes susceptible to this attack vector.
From an operational perspective, this vulnerability creates significant denial-of-service risks for systems that process TIFF images, particularly in environments where automated image handling is prevalent. Attackers can exploit this weakness by crafting specially formatted TIFF files that, when opened or processed by vulnerable applications, cause the LZW decoder to access invalid memory locations. This typically results in application crashes, process termination, or system instability that can be leveraged to disrupt service availability. The impact extends across various platforms and applications that depend on LibTIFF, including image viewers, document management systems, and content management platforms that handle TIFF file formats.
The mitigation strategy for CVE-2022-1623 involves applying the patch provided in commit b4e79bfa which addresses the out-of-bounds read condition through proper input validation and boundary checking within the LZWDecode function. System administrators should prioritize updating to the patched version of LibTIFF as soon as possible, particularly in environments where TIFF file processing occurs with untrusted input. Organizations should also implement input validation measures at the application level, where possible, to further reduce the attack surface. The fix demonstrates a classic approach to preventing buffer overflow vulnerabilities by ensuring that all memory accesses are properly bounded and validated before execution. This vulnerability serves as a reminder of the importance of robust input validation in image processing libraries and highlights the need for continuous security assessment of core system components that handle file format parsing and decoding operations.