A memory corruption issue was found in Artifex Ghostscript 9.50 and 9.52. Use of a non-standard PostScript operator can allow overriding of file access controls. The 'rsearch' calculation for the 'post' size resulted in a size that was too large, and could underflow to max uint32_t. This was fixed in commit 5d499272b95a6b890a1397e11d20937de000d31b.