CVE-2026-38332 in TinyEXIF
Summary
by MITRE • 09/13/2026
TinyEXIF before 1.1.0 has a heap-based buffer over-read in EntryParser::Fetch methods reachable via a crafted SubjectArea length.
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Analysis
by VulDB Data Team • 09/13/2026
The vulnerability identified in TinyEXIF versions prior to 1.1.0 represents a critical memory safety issue classified as a heap-based buffer over-read, technically corresponding to CWE-126. This flaw resides within the EntryParser::Fetch methods, which are responsible for parsing and extracting metadata fields from Exchangeable Image File Format (EXIF) data embedded in image files. The root cause of this vulnerability is an insufficient validation of the SubjectArea length field during the parsing process. When a maliciously crafted EXIF segment contains a malformed or excessively large length value that does not align with the actual available memory buffer, the parser proceeds to read beyond the allocated heap boundaries without performing adequate bounds checking.
From a technical perspective, this over-read occurs because the software fails to verify whether the requested data size exceeds the remaining capacity of the source buffer before initiating the copy or extraction operation. In C++ applications like TinyEXIF, such logic errors often stem from relying on untrusted input lengths directly as array indices or loop counters without cross-referencing them against the actual allocated memory size. Consequently, when an attacker supplies a crafted image file with a specifically engineered SubjectArea length field, the application attempts to access memory locations that lie outside the intended buffer region. This behavior allows for the leakage of sensitive information stored in adjacent heap memory blocks, which may contain stack canaries, pointers to other objects, or even parts of the program's own code structure.
The operational impact of this vulnerability extends beyond simple data exposure. While primarily categorized as an out-of-bounds read rather than a write, such flaws are frequently precursors to more severe exploitation scenarios. An attacker could potentially use the leaked memory contents to perform information disclosure attacks, gaining insights into the application's internal state or cryptographic keys if they reside in nearby heap regions. Furthermore, depending on how the parsed data is subsequently processed by the host application, this corrupted input might trigger secondary vulnerabilities such as integer overflows or null pointer dereferences during subsequent operations. In some contexts, carefully crafted payloads exploiting buffer over-reads can lead to denial of service conditions through segmentation faults if the operating system detects illegal memory access attempts.
This vulnerability aligns with several entries in the MITRE ATT&CK framework, particularly those related to initial exploitation and reconnaissance phases where attackers gather intelligence about the target environment. It also reflects common weaknesses found in media processing libraries that handle untrusted binary formats without rigorous input sanitization. The lack of strict boundary checks is a recurring theme in CWE-20 (Improper Input Validation) and highlights the risks associated with parsing complex, nested data structures like EXIF tags where length fields dictate memory access patterns.
To mitigate this vulnerability, developers must ensure that all version deployments are updated to TinyEXIF 1.1.0 or later, which addresses these specific bounds-checking deficiencies in the EntryParser::Fetch methods. For applications unable to immediately upgrade, implementing a robust input validation layer is essential. This involves verifying that any length field extracted from EXIF data does not exceed the size of the available buffer before attempting to read or copy the data. Additionally, employing static analysis tools and dynamic fuzzing techniques during the software development lifecycle can help identify similar logic errors in other parts of the codebase. Adopting safer memory management practices, such as using standard library containers that enforce bounds checking automatically, further reduces the risk of heap-based over-reads in future iterations of image processing software.