Description

TinyEXIF before 1.1.0 has a heap-based buffer over-read in EntryParser::Fetch methods reachable via a crafted SubjectArea length.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "2.9",
  "pubDate": "2026-09-13T21:17:01.460Z",
  "pubdate": "2026-09-13T21:17:01.460Z",
  "executiveSummary": "TinyEXIF versions prior to 1.1.0 are susceptible to a heap-based buffer over-read vulnerability within the EntryParser::Fetch methods.\nThis vulnerability is triggered when the library processes an image containing a maliciously crafted SubjectArea metadata field with an invalid length parameter.\nA remote attacker can leverage this flaw by providing a crafted image file to an application utilizing the TinyEXIF library.\nSuccessful exploitation may lead to unauthorized disclosure of sensitive information residing in heap memory, potentially including cryptographic keys, credentials, or other private data.\nThe vulnerability does not require authentication for exploitation, as it is triggered during the parsing of standard image file metadata.\nThe impact is primarily focused on information leakage, though depending on the application context, the leaked data could facilitate more complex attacks or compromise broader system security.\nRisk assessment suggests that any system parsing untrusted EXIF data with TinyEXIF versions below 1.1.0 is at potential risk.",
  "technicalDetails": "The vulnerability resides within the TinyEXIF metadata parsing engine, specifically targeting the EntryParser::Fetch methods. The flaw originates from insufficient bounds checking when processing EXIF tag data, specifically the SubjectArea tag. In the affected versions, the parser fails to adequately validate the length field associated with this tag before attempting to read data from the heap buffer.\nWhen a specially crafted EXIF payload is processed, the SubjectArea length value can be manipulated to exceed the actual allocation size of the buffer designated for holding the tag's data. Because the parser assumes the provided length is trustworthy and falls within the boundaries of the allocated heap space, it proceeds to read beyond the intended buffer limits.\nThe exploitation flow initiates when an application calls the TinyEXIF parsing function on an image file. The parser traverses the EXIF metadata segments and identifies the SubjectArea tag. The vulnerable EntryParser::Fetch method retrieves the length parameter directly from the file header or data segment without verifying that the length correlates with the expected structure or the size of the heap-allocated memory region.\nBy crafting a file where the SubjectArea length indicates a size larger than the actual tag data, an attacker forces the library to perform a heap-based buffer over-read. This operation allows the attacker to read the contents of adjacent heap memory, effectively leaking heap-resident data into the output or internal buffers.\nThe vulnerability exists in all TinyEXIF versions prior to 1.1.0. Exploitation is typically non-authenticated and can occur over any protocol that allows for the submission of images to a parser, such as web-based image uploads or local file system monitoring. There are no specific privilege requirements for triggering the read, as the vulnerability is inherent in the parsing logic itself.\nThe post-exploitation impact is primarily the compromise of confidentiality. By iteratively accessing or observing the output of the buffer over-read, an attacker may be able to extract sensitive data stored in the memory space of the host process, potentially leading to the leakage of system pointers, stack cookies, or data belonging to other components within the same process memory space."
}