CVE-2026-98354 RDMA/mad: Fix receive buffer leak when PKey enforcement fails
Remote attackers can cause memory leaks in the Linux kernel RDMA subsystem by sending invalid MADs, leading to resource exhaustion and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98354?
CVE-2026-98354 is a denial of service vulnerability in Linux, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
RDMA/mad: Fix receive buffer leak when PKey enforcement fails
ib_mad_complete_recv() initializes mad_recv_wc->rmpp_list and then runs ib_mad_enforce_security() before linking recv_buf onto that list. On failure it calls ib_free_recv_mad(), which only walks rmpp_list and frees the ib_mad_private of every buffer found there. As the list is still empty at that point, nothing is freed at all.
The caller cannot clean up either: ib_mad_recv_done() sets recv to NULL right after ib_mad_complete_recv() returns, assuming the MAD layer took ownership of the buffer. Every MAD that fails the PKey check therefore leaks one ib_mad_private (about 300 bytes per IB port MAD, ~2K for OPA), and a remote node can trigger this repeatedly by sending MADs with a wrong PKey.
Link recv_buf onto rmpp_list right after the list is initialized, so the error path has something to free.
Which versions are affected by CVE-2026-98354?
How do I fix CVE-2026-98354?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-98354 being exploited?
There is no known exploitation of CVE-2026-98354 in the wild and no public exploit code.
Sources
Also known as AZL-106290, BELL-CVE-2026-98354, DEBIAN-CVE-2026-98354, GHSA-q823-95hw-ffc6, UBUNTU-CVE-2026-98354.