CVE-2026-102805 in stb
Summary
by MITRE • 09/30/2026
A flaw has been found in Nothings stb up to 1.16. This affects the function stbi_write_png_to_mem/stbi_write_jpg_core/stbi_write_tga_core in the library stb_image_write.h of the component Image Encoding. Executing a manipulation can lead to integer overflow. The attack can be executed remotely. The exploit has been published and may be used.
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Analysis
by VulDB Data Team • 09/30/2026
The vulnerability identified in the stb image processing libraries, specifically affecting versions up to 1.16, represents a critical security risk within widely adopted single-header C/C++ software components. This flaw resides primarily in the encoding functions responsible for generating output files, namely stbi_write_png_to_mem, stbi_write_jpg_core, and stbi_write_tga_core found within the stb_image_write.h header file. These functions are integral to applications that need to convert image data into standard formats such as PNG, JPEG, or TGA for storage or transmission. The core technical deficiency is an integer overflow condition that occurs during memory allocation calculations performed by these encoding routines. When processing specific input parameters, the arithmetic operations used to determine buffer sizes can wrap around due to exceeding the maximum value representable by the integer type being used. This miscalculation leads to the allocation of a significantly smaller memory block than what is actually required for the encoded image data.
From an operational perspective, this integer overflow results in a heap-based buffer under-allocation. When the encoding process proceeds with insufficiently allocated memory, subsequent write operations will exceed the bounds of the allocated buffer. This condition constitutes a classic out-of-bounds write vulnerability, which can lead to severe consequences including application crashes, data corruption, and potentially arbitrary code execution if an attacker can control the content written beyond the buffer boundaries. The presence of published exploits indicates that this weakness is well-understood by malicious actors and can be reliably triggered in real-world scenarios. Because many applications utilize stb libraries for image manipulation tasks such as screenshot capture, asset generation, or file conversion, the attack surface is broad. An attacker could potentially craft a malformed input or manipulate application parameters to trigger the overflow during an encoding operation, thereby compromising the integrity of the host system.
The remote nature of this vulnerability suggests that it can be exploited without direct physical access to the target machine, provided there is a vector for delivering malicious inputs or triggering specific image processing workflows remotely. This aligns with common attack patterns where users are tricked into opening specially crafted files or interacting with web services that process images using vulnerable versions of stb libraries. The impact extends beyond simple denial of service; successful exploitation could allow an attacker to execute arbitrary code on the victim's system, leading to full compromise of confidentiality, integrity, and availability. This is particularly dangerous in environments where image processing is automated or performed as part of a larger pipeline without rigorous input validation at every stage.
Mitigation strategies must focus primarily on upgrading the stb libraries to patched versions that address these integer overflow issues. Developers should ensure that their build processes include updated headers from official repositories, verifying version numbers against known vulnerable ranges up to 1.16. In cases where immediate patching is not feasible, implementing strict input validation and bounds checking before invoking encoding functions can provide a layer of defense. Additionally, enabling compiler protections such as stack protectors and using memory-safe languages for new development efforts can reduce the risk associated with low-level buffer management errors. Security teams should also monitor for indicators of compromise related to image processing services and apply network-level controls to restrict access to vulnerable endpoints until patches are deployed.
This vulnerability is categorized under CWE-190, which describes integer overflow or wraparound, a common source of memory corruption bugs in C and C++ applications. The exploitation technique aligns with MITRE ATT&CK techniques related to buffer overflows and potentially code injection via heap manipulation. Understanding these classifications helps in mapping the risk to broader security frameworks and ensures that remediation efforts address both the immediate technical flaw and its potential use in larger attack chains involving privilege escalation or lateral movement within a compromised network environment.