Heap-based Buffer Overflow Affecting webmproject/libwebp package, versions [0.5.0,1.3.2)



    Attack Complexity Low
    Scope Changed
    Confidentiality High
    Integrity High
    Availability High

    Threat Intelligence

    Social Trends Trending on Twitter
    Exploit Maturity Mature
    EPSS 0.04% (7th percentile)
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8.8 high
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Red Hat
0 info

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  • published 26 Sep 2023
  • disclosed 25 Sep 2023
  • credit Apple SEAR, The Citizen Lab

How to fix?

Upgrade webmproject/libwebp to version 1.3.2 or higher.


Affected versions of this package are vulnerable to Heap-based Buffer Overflow. This advisory has been marked deprecated in favor of CVE-2023-4863

An attacker can craft a special WebP lossless file that triggers the ReadHuffmanCodes() function to allocate the HuffmanCode buffer with a size that comes from an array of precomputed sizes: kTableSize. The color_cache_bits value defines which size to use. The kTableSize array only takes into account sizes for 8-bit first-level table lookups but not second-level table lookups. libwebp allows codes that are up to 15-bit (MAX_ALLOWED_CODE_LENGTH). When BuildHuffmanTable() attempts to fill the second-level tables it may write data out-of-bounds. The OOB write to the undersized array happens in ReplicateValue().


This is only exploitable if the color_cache_bits value defines which size to use.

This vulnerability was first published on Chrome as CVE-2023-4863.


2023-09-26: Initial advisory publication

2023-09-27: Advisory details updated, including CVSS, CWE, references

2023-09-27: CVE-2023-5129 rejected as a duplicate of CVE-2023-4863

2023-09-28: This advisory has been marked deprecated in favor of CVE-2023-4863