CVE-2026-99192 net: bcmgenet: unshare the skb before writing the control block
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-99192?
CVE-2026-99192 is a vulnerability in Linux, published on 28 Oct 2026.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net: bcmgenet: unshare the skb before writing the control block
bcmgenet stores first_cb, last_cb and bytes_sent in the skb control block and reads them back on completion to free the skb and credit BQL. ether_setup() leaves IFF_TX_SKB_SHARING set, so the stack can resubmit a shared skb that is still in the ring. The next transmit overwrites last_cb, so the earlier slots complete without crediting their bytes and BQL stalls the queue until the watchdog resets it.
Unshare the skb before writing the control block.
Reproduce with pktgen in clone_skb mode, which hands the driver the same skb while earlier copies are still in the ring:
modprobe pktgen pg=/proc/net/pktgen echo "add_device eth0" > $pg/kpktgend_0 echo "dst_mac AA:BB:CC:DD:EE:FF" > $pg/eth0 echo "dst 192.0.2.1" > $pg/eth0 echo "clone_skb 8" > $pg/eth0 echo "count 0" > $pg/eth0 echo start > $pg/pgctrl & sleep 5 echo stop > $pg/pgctrl wait cat /sys/class/net/eth0/queues/tx-0/byte_queue_limits/inflight
inflight stays nonzero on the now idle queue. clone_skb 0 leaves it at zero.
Which versions are affected by CVE-2026-99192?
How do I fix CVE-2026-99192?
Upgrade to a fixed version.
Is CVE-2026-99192 being exploited?
There is no known exploitation of CVE-2026-99192 in the wild and no public exploit code.
Sources
Also known as AZL-111359, BELL-CVE-2026-99192, DEBIAN-CVE-2026-99192, GHSA-gcjx-rww2-6xmm, UBUNTU-CVE-2026-99192.