CVE-2026-90417: RDMA/cxgb4: Fix dereg_skb leak and double free in write_tpt_entry()

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-17 · updated 2026-10-30

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().

Affected products

Linux: 4.8 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux 7.3. Check the vendor advisory for mitigations.

References

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