Use-after-free in Linux mac80211 channel context reserved switch
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 1 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The mac80211 Wi-Fi subsystem in the Linux kernel is affected in versions from 3.17 before the fixed releases. The function ieee80211_vif_use_reserved_switch counts links with reservations that belong to a different replacement operation, so a channel context replacement can look complete too early. This can free a channel context that an unmatched link still uses, leading to a use-after-free at a later step.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: count only matching reservations in reserved switch ieee80211_vif_use_reserved_switch() validates a replacement by counting assigned links on ctx->replace_ctx and treating reservations too broadly. A link can still be assigned to the old channel context while holding a reservation that belongs to a different replacement operation. That can make the current replacement appear complete too early. If another link finalizes first, the function can free the WILL_BE_REPLACED chanctx while the unmatched link and driver still use it, leading to a use-after-free in later beacon generation. Require an in-place reservation to point at the current replacement context, and require the reserved and assigned contexts to be the matching replacement pair, before counting or moving the link.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 3.17 and later | 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 3.17 and later Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3 Patch available CNA
Remediation
Upgrade the Linux kernel to 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10 or 7.3. Red Hat Enterprise Linux 10 is affected, and the sources list no fixed version for it.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
- Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98709
- 2026-10-18 Alias added: GHSA-g34c-vjm7-4vq5
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@4ae6ed5b6074df5f3da05fd74c40bb24c5c9b41d, Linux/[email protected] · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-21 Affected versions changed · Red Hat
- 2026-10-21 CVSS score added · Red Hat
- 2026-10-30 Fix available: Linux/Linux@183cc72ae9467717afba8b8d194a558a6666cb53, Linux/Linux@4c4671a706d2d85442a30850abfada5377ffbbc8, Linux/[email protected] +3 · CNA
- 2026-10-30 3 new references · CNA
References
Other 8
- https://git.kernel.org/stable/c/4c4671a706d2d85442a30850abfada5377ffbbc8
- https://git.kernel.org/stable/c/183cc72ae9467717afba8b8d194a558a6666cb53
- https://git.kernel.org/stable/c/b3d9f582f98e06070d5233b177b2899b693a01ec
- https://git.kernel.org/stable/c/4ae6ed5b6074df5f3da05fd74c40bb24c5c9b41d
- https://git.kernel.org/stable/c/d31f655e44631891788ca67018ec5e1ed1c7de86
- https://git.kernel.org/stable/c/03525b632908b049f4d04cc8a71cdff2329589cf
- https://git.kernel.org/stable/c/5cc54a000960bc88f8c58940164dca0e601ab39c
- https://git.kernel.org/stable/c/437f3727b4fd715266c296435c116288f82666fd
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Sources
- CVE-2026-98709 · CVE Program
- CVE-2026-98709 · NVD
- FIRST EPSS
- GHSA-g34c-vjm7-4vq5 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98709 · Red Hat security data · CC BY 4.0
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