CVE-2026-74378 RDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe
A race condition in the Linux kernel RDMA driver allows local attackers to trigger a heap overflow, potentially leading to code execution or privilege escalation.
- 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-2026-74378?
CVE-2026-74378 is a high-severity vulnerability in Linux, published on 15 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:
RDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe
get_srq_wqe() reads wqe->dma.num_sge from the shared receive queue buffer, which is mapped into userspace. It validates num_sge against max_sge, but then re-reads the same field to calculate the memcpy size. A concurrent userspace thread can modify num_sge between validation and use, causing a heap buffer overflow when copying the WQE into qp->resp.srq_wqe.
Read num_sge into a local variable and use it for both the bounds check and the size calculation.
Which versions are affected by CVE-2026-74378?
How do I fix CVE-2026-74378?
Apply the vendor's patch.
Is CVE-2026-74378 being exploited?
There is no known exploitation of CVE-2026-74378 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74378, DEBIAN-CVE-2026-74378, GHSA-7vv8-3m2v-67j6, UBUNTU-CVE-2026-74378.