CVE-2026-52908
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
In the Linux kernel, a vulnerability was found in the MR re-registration mechanism in RDMA drivers. When changing access permissions from read-only (RO) to read-write (RW), the consistency of the user memory mapping (umem) was not verified, potentially leading to improper page pinning.
Risk Assessment
The organization may face data integrity violations or unauthorized memory writes if a process using RDMA changes MR permissions without proper validation. This could enable privilege escalation or data leakage.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit adding ib_umem_check_rereg() function). For the mlx4 driver, avoid the IB_MR_REREG_ACCESS | IB_MR_REREG_TRANS combination, which is not supported.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: RDMA: During rereg_mr ensure that REREG_ACCESS is compatible If IB_MR_REREG_ACCESS changes from RO to RW then the umem has to be re-evaluated to ensure it is properly pinned as RW. Since the umem is hidden inside each driver's mr struct add a ib_umem_check_rereg() function that each driver has to call before processing IB_MR_REREG_ACCESS. mlx4 has to retain its duplicate ib_access_writable check because it implements IB_MR_REREG_ACCESS | IB_MR_REREG_TRANS by changing both items in place sequentially while the MR is live, so it will continue to not support this combination.