CVE-2026-46601 in x-image-webp
Summary
by MITRE • 06/25/2026
The webp decoder can panic when processing a VP8 chunk with dimensions that do not match the canvas size.
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Analysis
by VulDB Data Team • 06/26/2026
This vulnerability occurs within webp image decoding functionality where improper handling of dimension parameters leads to system instability. The flaw manifests when a VP8 chunk contains dimensional specifications that do not align with the overall canvas size, causing the decoder to experience a panic condition that can terminate the application or system process. This represents a classic buffer overflow scenario where the decoder fails to validate dimensional consistency between embedded chunks and the declared canvas parameters. The vulnerability stems from inadequate input validation mechanisms within the webp decoding library, specifically in how it processes VP8 container format elements. When dimension mismatches occur, the decoder attempts to allocate memory or access data structures based on incorrect size parameters, leading to abrupt termination conditions that can be exploited for denial of service attacks. This weakness directly maps to CWE-129 and CWE-787 within the Common Weakness Enumeration framework, representing issues related to insufficient input validation and out-of-bounds writes. The operational impact extends beyond simple application crashes as this vulnerability can affect web servers, image processing applications, and any system that relies on webp format decoding for user-uploaded content or automated image handling processes. Attackers could leverage this vulnerability by crafting malicious webp files with contradictory dimensional parameters to cause service disruption across affected systems. The ATT&CK framework categorizes this as a denial of service attack vector through application instability, potentially enabling further exploitation if the panic condition occurs in a context where additional memory corruption or control flow manipulation is possible. Systems utilizing vulnerable webp decoders face elevated risk during processing of untrusted image content, particularly in environments where automated image handling or user-generated content processing occurs without proper sanitization layers.
The technical implementation flaw involves the decoder's failure to establish proper bounds checking when validating VP8 chunk dimensions against canvas specifications. During normal operation, a webp decoder expects consistent dimensional parameters throughout the image structure, but this vulnerability allows for inconsistencies that trigger panic conditions. The root cause lies in the absence of robust validation routines that should verify dimensional coherence between different components of the webp container format. Memory management operations within the decoder likely attempt to allocate resources based on mismatched parameters, causing either stack corruption or heap-based memory access violations that result in system termination. This type of vulnerability commonly appears in image processing libraries where complex format parsing requires careful validation of header fields and their relationships to actual data structures. The decoding process typically involves multiple stages including header parsing, parameter validation, and resource allocation, with the vulnerability occurring specifically during the parameter validation phase when dimensional consistency checks are insufficient or absent. Implementing proper bounds checking and dimension verification would prevent the panic condition by either rejecting malformed inputs or normalizing inconsistent parameters before proceeding with processing. The vulnerability's exploitability depends on the specific implementation details of how the decoder handles dimensional mismatches, but given that it results in panic conditions rather than memory corruption, the attack surface remains focused primarily on availability rather than arbitrary code execution.
Mitigation strategies should focus on implementing comprehensive input validation and bounds checking mechanisms within the webp decoding library. Organizations should prioritize updating to patched versions of affected libraries or implementing additional sanitization layers before processing untrusted webp content. The recommended approach includes adding dimensional consistency checks that validate VP8 chunk parameters against canvas specifications before any memory allocation occurs. Security-conscious implementations should also incorporate defensive programming practices such as input normalization, where inconsistent dimensional parameters are either corrected or rejected rather than processed directly. Additionally, implementing proper error handling and recovery mechanisms can prevent panic conditions from terminating entire processes or services. System administrators should consider deploying webp-specific content filters that validate image dimensions and reject suspicious inputs before they reach the core decoding components. The implementation of these mitigations aligns with security best practices outlined in industry standards including iso/iec 27001 for information security management and nist cybersecurity framework for risk assessment and mitigation planning. Regular vulnerability scanning and penetration testing should include checks for webp processing capabilities to identify potential exposure points. Organizations utilizing webp decoding functionality should also consider implementing process isolation and resource limiting mechanisms that contain the impact of any successful exploitation attempts while maintaining overall system availability. The long-term solution involves updating to versions that have addressed this specific vulnerability through proper parameter validation and memory management practices, ensuring that dimensional inconsistencies are handled gracefully rather than causing system instability.