Vulnerability in Artifex Software MuJS

[ Why it matters ]Priority signals

• Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

MuJS 1.3.6 before 1.3.9 contains a heap out-of-bounds read and write vulnerability in Array.prototype.sort that allows attackers to corrupt memory by inflating a simple array's length. Attackers can supply JavaScript that enlarges a dense array's length and calls sort, causing Ap_sort_cmp and Ap_sort_swap to access slots past the buffer and crash the process.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References

• codeberg.org/ccxvii/mujs
• codeberg.org/ccxvii/mujs/commit/32064e10caa45e68fc87331ca53d042049cc9396
• codeberg.org/ccxvii/mujs/src/commit/307f18c4216420f2f56e22d8e7040baa39a6304a/jsarray.c
• hackmd.io/@haind-pwn/mujs-array-length-flat-oob
• mujs.com/downloads
• www.vulncheck.com/advisories/mujs-1.3.6-before-1.3.9-heap-out-of-bounds-read-write-via-…