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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-15900
• ArtifexSoftware/ghostpdl@5d49927
• https://artifex.com/security-advisories/CVE-2020-15900
• https://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=5d499272b95a6b890a1397e11d20937de000d31b
• https://github.com/ArtifexSoftware/ghostpdl/commits/master/psi/zstring.c
• https://security.gentoo.org/glsa/202008-20
• https://usn.ubuntu.com/4445-1/
• http://git.ghostscript.com/?p=ghostpdl.git;a=log
• http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00004.html
• http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00006.html