CVE-2026-90417 RDMA/cxgb4: Fix dereg_skb leak and double free in write_tpt_entry()
A double free and memory leak in the Linux kernel's cxgb4 RDMA driver can lead to system crashes or potential code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90417?
CVE-2026-90417 is an use after free vulnerability in Linux, published on 17 Sep 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/cxgb4: Fix dereg_skb leak and double free in write_tpt_entry()
When the device is in the fatal error state, write_tpt_entry() returns -EIO before handing the caller's preallocated skb to the transmit path; its allocation-failure returns do the same. c4iw_dereg_mr() ignores the error and frees mhp, leaking mhp->dereg_skb. c4iw_get_dma_mr() instead frees the skb a second time after dereg_mem() already consumed it, a double free.
Make write_tpt_entry() the sole owner of a non-NULL skb, freeing it on every return preceding handoff to c4iw_ofld_send(): fatal error, tpt and stag allocation failure. c4iw_ofld_send() consumes the skb on success and error alike, so drop the redundant kfree_skb() in c4iw_get_dma_mr() after dereg_mem().
Which versions are affected by CVE-2026-90417?
How do I fix CVE-2026-90417?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-90417 being exploited?
There is no known exploitation of CVE-2026-90417 in the wild and no public exploit code.
Sources
Also known as AZL-102695, BELL-CVE-2026-90417, DEBIAN-CVE-2026-90417, GHSA-ccpx-w89w-v2mx, UBUNTU-CVE-2026-90417.