CVE-2026-89793

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An issue exists in the ublk ch mmap() function where it fails to clear the VM MAYWRITE flag on read-only mappings. This allows an unprivileged userspace daemon to map the per-queue command buffer with PROT READ and subsequently upgrade the permissions to PROT WRITE using the mprotect() function. Because the command buffer contains ublk srv io desc entries that are kernel-written ABI, a writable mapping enables a process to corrupt critical fields including addr, op flags, nr sectors, and start sector.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.