In the Linux kernel, the following vulnerability has been resolved:

drm/vmwgfx: Fix possible null pointer derefence with invalid contexts

vmw_context_cotable can return either an error or a null pointer and its
usage sometimes went unchecked. Subsequent code would then try to access
either a null pointer or an error value.

The invalid dereferences were only possible with malformed userspace
apps which never properly initialized the rendering contexts.

Check the results of vmw_context_cotable to fix the invalid derefs.

Thanks:
ziming zhang(@ezrak1e) from Ant Group Light-Year Security Lab
who was the first person to discover it.
Niels De Graef who reported it and helped to track down the poc.

kernel.org https://git.kernel.org/stable/c/07c3fe923ff7eccf684fb4f8c953d0a7cc8ded73 [No types assigned]

kernel.org https://git.kernel.org/stable/c/517621b7060096e48e42f545fa6646fc00252eac [No types assigned]

kernel.org https://git.kernel.org/stable/c/585fec7361e7850bead21fada49a7fcde2f2e791 [No types assigned]

kernel.org https://git.kernel.org/stable/c/899e154f9546fcae18065d74064889d08fff62c2 [No types assigned]

kernel.org https://git.kernel.org/stable/c/9cb3755b1e3680b720b74dbedfac889e904605c7 [No types assigned]

kernel.org https://git.kernel.org/stable/c/c560327d900bab968c2e1b4cd7fa2d46cd429e3d [No types assigned]

kernel.org https://git.kernel.org/stable/c/ff41e0d4f3fa10d7cdd7d40f8026bea9fcc8b000 [No types assigned]