CVE-2026-80988: NTB: ntb_transport: Fail TX enqueue when the QP link is down

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: 2026-09-11 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: NTB: ntb_transport: Fail TX enqueue when the QP link is down Commit f195a1a6fe41 ("ntb: Drop packets when qp link is down") meant to make ntb_transport_tx_enqueue() drop packets submitted while the QP link is down, but it only returns 0 without consuming the packet. Zero means success by this function's contract, so ntb_netdev reports NETDEV_TX_OK and forgets the skb: nothing queued it, nothing frees it, and it leaks, one skb for every transmit racing a link-down. Return -ENOLINK instead, restoring the contract that a non-zero return leaves the buffer owned by the caller. With the preceding patch, ntb_netdev frees the skb on non-retryable enqueue failures and returns NETDEV_TX_OK, so a packet racing with link-down is dropped without leaking or entering a busy retry loop.

Affected products

Linux kernel: from 5.10.195 before 5.10.270; from 5.15.132 before 5.15.221; from 6.1.53 before 6.1.188; from 4.14.326 before 4.15; from 4.19.295 before 4.20; from 5.4.257 before 5.5 — fixed in 4.15, 4.20, 5.10.270, 5.15.221, 5.5, 6.1.188

How to fix

Upgrade to a fixed version: Linux kernel 4.15, 4.20, 5.10.270, 5.15.221. Check the vendor advisory for mitigations.

References

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