Potential Heap Overwrite Vulnerability in MKV Demuxing with Bzip Decompression

CVE-2022-1923 · HIGH Severity

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

DOS / potential heap overwrite in mkv demuxing using bzip decompression. Integer overflow in matroskademux element in bzip decompression function which causes a segfault, or could cause a heap overwrite, depending on libc and OS. Depending on the libc used, and the underlying OS capabilities, it could be just a segfault or a heap overwrite. If the libc uses mmap for large chunks, and the OS supports mmap, then it is just a segfault (because the realloc before the integer overflow will use mremap to reduce the size of the chunk, and it will start to write to unmapped memory). However, if using a libc implementation that does not use mmap, or if the OS does not support mmap while using libc, then this could result in a heap overwrite.

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