CVE-2026-98850 net/packet: prevent TX_RING byte count overflow
A local attacker with CAP_NET_RAW can trigger an integer overflow in the Linux kernel packet socket implementation, causing a kernel panic and denial of service.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98850?
CVE-2026-98850 is a vulnerability in Linux, published on 18 Oct 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:
net/packet: prevent TX_RING byte count overflow
tpacket_snd() drains every SEND_REQUEST frame in a TX ring and adds each valid packet length to the signed int len_sum. Userspace can recycle completed frames concurrently, so a single blocking send call is not bounded by the ring size.
After enough successful transmissions len_sum wraps into the negative range. In particular, 65536 65535-byte frames followed by a 65007-byte frame produce 0xfffffdef, or -EIOCBQUEUED. sock_sendmsg_nosec() treats that as an impossible return and triggers a BUG. On systems configured to panic on oops, a CAP_NET_RAW holder can panic the host kernel.
Stop before the next frame would make the byte count exceed INT_MAX. The positive short count leaves that frame pending for a later send call.
A two-thread TPACKET_V2 reproducer triggered the BUG on an arm64 build of Linux 7.3-rc4. With this change, the same reproducer returned the expected positive short count without an oops.
Which versions are affected by CVE-2026-98850?
How do I fix CVE-2026-98850?
Apply the vendor's patch.
Is CVE-2026-98850 being exploited?
There is no known exploitation of CVE-2026-98850 in the wild and no public exploit code.
Sources
Also known as AZL-108860, BELL-CVE-2026-98850, DEBIAN-CVE-2026-98850, GHSA-prpm-w567-3rvc, UBUNTU-CVE-2026-98850.