In case you missed the news, there’s a critical 0day in WebP (a heap buffer overflow in the libwepb library) floating about, which was initially issued as CVE-2023-4863 and assigned specifically to Google Chrome. At the time this happened, I wrote my blog post about it and vehemently tried to make it clear that it wasn’t just Chrome that was affected, but any software that uses libwebp to render WebP images.

That story exploded. 🤯

I’ve just taken note that Google has issued a separate CVE, which is tracked under CVE-2023-5129,

With a specially crafted WebP lossless file, libwebp may write data out of bounds to the heap. The ReadHuffmanCodes() function allocates 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.

Important: If you’re a news