CVE-2026-110597 in TinyEXR
Summary
by MITRE • 10/15/2026
Tinyexr through 3.2.0 contains a heap out-of-bounds read vulnerability in ParseEXRMultipartHeaderFromMemory() that allows attackers to read beyond buffers due to a stale remaining-size value. Attackers can supply a crafted multi-part EXR file whose later part headers bypass ReadAttribute() bounds checks, crashing applications or leaking adjacent heap memory into attribute values.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified in TinyEXR versions through 3.2.0 represents a critical security flaw within the library's handling of OpenEXR image files, specifically targeting the multipart header parsing logic. The core issue resides in the ParseEXRMultipartHeaderFromMemory function, which is responsible for interpreting the structural metadata of multi-part EXR documents. In this context, an attacker can construct a maliciously crafted file where the internal state tracking the remaining size of data to be processed becomes stale or inconsistent with actual buffer boundaries. This discrepancy arises because the logic fails to properly validate that the declared length of subsequent parts aligns with the available memory space defined by earlier headers. Consequently, when the parser proceeds to read attribute values from these later sections, it relies on incorrect boundary calculations derived from this outdated size metric rather than performing strict bounds checking against the actual allocated heap buffer.
This technical flaw directly facilitates a heap out-of-bounds read condition, which is categorized under CWE-125 in standard vulnerability classification systems. The operational impact of such an error extends beyond simple application instability. When the parser attempts to access memory locations that lie outside the intended allocation, it may successfully retrieve data from adjacent regions of the heap. This behavior enables information disclosure attacks where sensitive or arbitrary memory contents are leaked into attribute values within the parsed object structure. Furthermore, if the out-of-bounds read triggers a segmentation fault due to accessing unmapped pages, it results in a denial of service by crashing the host application that utilizes TinyEXR for image processing. Such crashes can be exploited to disrupt services relying on automated image ingestion pipelines or cause instability in desktop applications handling user-supplied EXR files.
From an offensive security perspective, this vulnerability aligns with techniques observed in ATT&CK framework mappings related to memory corruption and data exfiltration via malformed inputs. The ability to read arbitrary heap memory can serve as a primitive for further exploitation chains, potentially aiding in bypassing stack-based protections or facilitating more complex attacks if combined with other weaknesses like use-after-free scenarios. Although the primary manifestation described is an out-of-bounds read rather than a write, the leakage of internal application state provides attackers with valuable intelligence about the memory layout and loaded modules, which can be leveraged to refine subsequent exploitation attempts against the target system.
Mitigation strategies for this vulnerability require immediate updates to the TinyEXR library version 3.2.0 or later, where developers have addressed the stale remaining-size logic by implementing rigorous validation checks before processing multipart headers. Developers integrating this library into their applications should ensure that dependency management systems are configured to pull these patched versions automatically. Additionally, defense-in-depth measures such as enabling Address Sanitizer during testing phases can help detect similar boundary violations in custom code paths. For environments where immediate patching is not feasible, input validation filters at the application layer should be employed to reject EXR files with suspiciously large or inconsistent header sizes before they are passed to the parsing engine. Regular security audits of image processing components and adherence to secure coding practices that emphasize strict bounds checking on all external inputs remain essential for preventing exploitation of such memory safety issues.