CVE-2026-98709 - Vulnerability Details

- wifi: mac80211: count only matching reservations in reserved switch

Description

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.

Published: 2026-10-18

Score: 4.7 Medium

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

The vulnerability resides in the Linux kernel’s mac80211 module and exploits a logic error in reservation counting during channel replacement operations. When a link’s reservation does not match the replacement context, the kernel may prematurely finalize a replacement, freeing a channel context that is still in use. This results in a use‑after‑free during beacon generation, which can crash the kernel and potentially lead to denial of service or privilege escalation. The weakness is a classic use‑after‑free (CWE‑416).

Affected Systems

The flaw affects all Linux kernel builds that include the mac80211 module, regardless of distribution. No specific kernel versions are listed in the data, so any kernel that has not applied the listed patch is susceptible. The issue impacts wireless drivers that rely on mac80211 and can influence any system with enabled Wi‑Fi hardware.

Risk and Exploitability

The CVSS score of 4.7 indicates moderate severity, while the EPSS score is less than 1% and the vulnerability is not listed in KEV. The bug causes the kernel to prematurely finalize a channel replacement, freeing a channel context that is still in use, leading to a use‑after‑free during subsequent beacon emission. Exploitation would require the attacker to influence Wi‑Fi channel replacement—for instance, by sending crafted management frames or triggering replacement conditions—to trigger the race condition. No publicly available exploits are known, but the kernel could crash or become unstable if the condition is met.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f`	affected	< 4c4671a706d2d85442a30850abfada5377ffbbc8
`5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f`	affected	< 183cc72ae9467717afba8b8d194a558a6666cb53
`5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f`	affected	< b3d9f582f98e06070d5233b177b2899b693a01ec
`5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f`	affected	< 4ae6ed5b6074df5f3da05fd74c40bb24c5c9b41d
`5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f`	affected	< d31f655e44631891788ca67018ec5e1ed1c7de86
`5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f`	affected	< 03525b632908b049f4d04cc8a71cdff2329589cf
`5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f`	affected	< 5cc54a000960bc88f8c58940164dca0e601ab39c
`5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f`	affected	< 437f3727b4fd715266c296435c116288f82666fd

Linux

affected

Version	Status	Constraints
`3.17`	affected	—
`0`	unaffected	< 3.17
`5.10.273`	unaffected	≤ 5.10.*
`5.15.224`	unaffected	≤ 5.15.*
`6.1.191`	unaffected	≤ 6.1.*
`6.6.160`	unaffected	≤ 6.6.*
`6.12.113`	unaffected	≤ 6.12.*
`6.18.56`	unaffected	≤ 6.18.*
`7.2.10`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f,d31f655e44631891788ca67018ec5e1ed1c7de86)`	affected	code_commit	—
`[5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f,03525b632908b049f4d04cc8a71cdff2329589cf)`	affected	code_commit	—
`[5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f,5cc54a000960bc88f8c58940164dca0e601ab39c)`	affected	code_commit	—
`[5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f,437f3727b4fd715266c296435c116288f82666fd)`	affected	code_commit	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`3.17`	affected	generic	—
`[0,3.17)`	unaffected	generic	—
`[6.12.113,6.13.0)`	unaffected	semver	—
`[6.18.56,6.19.0)`	unaffected	semver	—
`[7.2.10,7.3.0)`	unaffected	semver	—
`[7.3-rc6,*]`	unaffected	generic	—

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Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade the Linux kernel to a release that contains the mac80211 patch fixing reservation counting.
Ensure all Wi‑Fi firmware and associated kernel modules are updated to the same patched kernel version.
As a temporary measure, disable or unbind Wi‑Fi interfaces until the kernel update is applied.
Monitor system logs for kernel panic or OOM events that may indicate a use‑after‑free was triggered.

Generated by OpenCVE AI on October 22, 2026 at 21:05 UTC.

Tracking

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Advisories

Source	ID	Title
Debian DLA	DLA-4850-1	linux-6.12 security update

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00176.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/03525b632908b049f4d04cc8a71cdff2329589cf
https://git.kernel.org/stable/c/183cc72ae9467717afba8b8d194a558a6666cb53
https://git.kernel.org/stable/c/437f3727b4fd715266c296435c116288f82666fd
https://git.kernel.org/stable/c/4ae6ed5b6074df5f3da05fd74c40bb24c5c9b41d
https://git.kernel.org/stable/c/4c4671a706d2d85442a30850abfada5377ffbbc8
https://git.kernel.org/stable/c/5cc54a000960bc88f8c58940164dca0e601ab39c
https://git.kernel.org/stable/c/b3d9f582f98e06070d5233b177b2899b693a01ec
https://git.kernel.org/stable/c/d31f655e44631891788ca67018ec5e1ed1c7de86
https://kernelcve.org/list/?q=CVE-2026-98709
https://nvd.nist.gov/vuln/detail/CVE-2026-98709
https://www.cve.org/CVERecord?id=CVE-2026-98709

History

Fri, 30 Oct 2026 12:45:00 +0000

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/183cc72ae9467717afba8b8d194a558a6666cb53 https://git.kernel.org/stable/c/4c4671a706d2d85442a30850abfada5377ffbbc8 https://git.kernel.org/stable/c/b3d9f582f98e06070d5233b177b2899b693a01ec

Thu, 22 Oct 2026 12:30:00 +0000

Type	Values Removed	Values Added
References		https://kernelcve.org/list/?q=CVE-2026-98709 https://nvd.nist.gov/vuln/detail/CVE-2026-98709 https://www.cve.org/CVERecord?id=CVE-2026-98709
Metrics	threat_severity `None`	cvssV3_1 `{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}` threat_severity `Moderate`

Wed, 21 Oct 2026 13:15:00 +0000

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/4ae6ed5b6074df5f3da05fd74c40bb24c5c9b41d

Sun, 18 Oct 2026 19:45:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-416

Sun, 18 Oct 2026 16:00:00 +0000

Type	Values Removed	Values Added
Description		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.
Title		wifi: mac80211: count only matching reservations in reserved switch
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/03525b632908b049f4d04cc8a71cdff2329589cf https://git.kernel.org/stable/c/437f3727b4fd715266c296435c116288f82666fd https://git.kernel.org/stable/c/5cc54a000960bc88f8c58940164dca0e601ab39c https://git.kernel.org/stable/c/d31f655e44631891788ca67018ec5e1ed1c7de86

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-10-18T15:46:39.290Z

Updated: 2026-10-30T12:39:00.231Z

Reserved: 2026-09-25T10:25:14.365Z

Link: CVE-2026-98709

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-10-18T16:17:24.437

Modified: 2026-10-30T13:21:20.337

Link: CVE-2026-98709

Redhat

Severity : Moderate

Publid Date: 2026-10-18T15:46:39Z

Links: CVE-2026-98709 - Bugzilla

OpenCVE Enrichment

Updated: 2026-10-22T21:15:12Z

Weaknesses

CWE-416
Use After Free

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

Subscriptions

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