CVE-2026-80998 net: bnxt: ring the doorbell when SW USO exits early
A bug in the Linux kernel bnxt network driver can cause TX queue stalls, leading to 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-2026-80998?
CVE-2026-80998 is a high-severity denial of service vulnerability in Linux, published on 11 Sep 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:
net: bnxt: ring the doorbell when SW USO exits early
When a burst of packets is handed down to the driver, the driver defers the doorbell to the end by setting txr->kick_pending = 1. The normal TX path handles this, but the SW USO path can miss it if it returns early.
If bnxt_sw_udp_gso_xmit runs but returns early with NETDEV_TX_BUSY and txr->kick_pending was previously set to 1, then the TX queue can stall because the driver wrote some BDs but never wrote the doorbell. The device won't know to do the TX which would generate the completion that would wake the queue back up.
Simplify bnxt_sw_udp_gso_xmit to set txr->kick_pending in its success case and check the flag on return. The added check after bnxt_sw_udp_gso_xmit returns ensures that any pending doorbells are written handling both successful USO and any early returns, which prevents the TX queue stall mentioned above.
This TX queue stall was observed on a production system with a netdev TX watchdog informing about the queue stall.
Which versions are affected by CVE-2026-80998?
How do I fix CVE-2026-80998?
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-2026-80998 being exploited?
There is no known exploitation of CVE-2026-80998 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-80998, GHSA-853c-vx6w-q6cv, UBUNTU-CVE-2026-80998.