CVE-2026-80701 drm/vmwgfx: enforce cursor size limits for MOB cursors
A local attacker with DRM master access can trigger a kernel null pointer dereference and system crash by requesting oversized cursors in the vmwgfx driver.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80701?
CVE-2026-80701 is a vulnerability in Linux, published on 28 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
drm/vmwgfx: enforce cursor size limits for MOB cursors
vmw_cursor_plane_atomic_check() bounds cursor width and height only on the legacy update path; the SVGA_CAP2_CURSOR_MOB path -- the default on modern hosts -- accepts any size. When the requested size exceeds SVGA_REG_CURSOR_MAX_DIMENSION or SVGA_REG_MOB_MAX_SIZE, vmw_cursor_mob_get() returns -EINVAL and leaves vps->cursor.mob NULL. Its return value is then discarded in vmw_cursor_plane_prepare_fb(), so the subsequent vmw_cursor_update_mob() calls vmw_bo_map_and_cache(NULL) and oopses inside vmw_bo_map_and_cache_size() on the tbo.base.size load.
Reachable from any DRM master via DRM_IOCTL_MODE_CURSOR2 with a sufficiently large width or height (e.g. cursor_max_dim + 1).
Reject oversized cursors in atomic_check for both MOB-backed cursor update types. The MOB byte-size limit only applies to the SVGA_CAP2_CURSOR_MOB path (vmw_cursor_mob_size() returns 0 for GB_ONLY); compute the required MOB size in 64-bit to avoid overflow when very large dimensions are requested.
In prepare_fb only call vmw_cursor_mob_get()/_map() for VMW_CURSOR_UPDATE_MOB -- the GB_ONLY path uses bo->map.virtual directly and would otherwise be silently downgraded to NONE on hosts without SVGA_CAP2_CURSOR_MOB (where vmw_cursor_mob_get() always returns -EINVAL). Degrade the update to NONE if vmw_cursor_mob_get() or vmw_cursor_mob_map() fails so the update path does not run with a NULL backing MOB.
Which versions are affected by CVE-2026-80701?
How do I fix CVE-2026-80701?
Apply the vendor's patch.
Is CVE-2026-80701 being exploited?
There is no known exploitation of CVE-2026-80701 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-80701, DEBIAN-CVE-2026-80701, GHSA-xr66-5v48-7crq, UBUNTU-CVE-2026-80701.