# CVE-2026-80980

## Summary

- **CVE ID:** CVE-2026-80980
- **Severity:** CRITICAL
- **CVSS Score:** 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 13, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:

net/smc: stop killed, freed and out_of_sync sharing a byte

The three connection state flags are single-bit bitfields, so they occupy
one byte of struct smc_connection and every store to one is a
read-modify-write of the other two:

    u8  killed : 1;
    u8  freed : 1;
    u8  out_of_sync : 1;

They are not written under a common lock. smc_cdc_msg_validate() sets
out_of_sync from the receive tasklet, while smc_conn_kill() sets killed
from process context under lock_sock(), and the receive path does not defer
to the backlog when the socket is owned -- smc_cdc_msg_recv() takes only
bh_lock_sock().

Give each flag its own byte so a store no longer touches its neighbours.
All readers test them as booleans and are unchanged. struct smc_connection
grows by two bytes.

## Affected Products

- Linux — Linux (b286a0651e4404ab96cdfdcdad8a839a26b3751e)
- Linux — Linux (5.8)
- Linux — Linux (0)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)

## References

- [CNA](https://git.kernel.org/stable/c/313f79149eb337411c64e2c247234b62ef9a3cb9)
- [CNA](https://git.kernel.org/stable/c/2cb7a8d64b7e8ccdc69bbe48fe9c4eaa79c33aec)
- [CNA](https://git.kernel.org/stable/c/db51a8658c11a82432b64999519a269c3aabb447)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.60%
- **EPSS Percentile:** 47.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._