CVE-2021-20292

There is a flaw reported in the Linux kernel in versions before 5.9 in drivers/gpu/drm/nouveau/nouveau_sgdma.c in nouveau_sgdma_create_ttm in Nouveau DRM subsystem. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker with a local account with a root privilege, can leverage this vulnerability to escalate privileges and execute code in the context of the kernel.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://bugzilla.redhat.com/show_bug.cgi?id=1939686
• https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html
• https://bugzilla.redhat.com/show_bug.cgi?id=1939686
• https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html