VulnerabilityPublished 23 Oct 2026

CVE-2026-99035: Linux kernel · mmc: mtk-sd: Cancel request timeout work on remove

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in f37e0367ad6f2147a0b37564b442b7a25bec0d23 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:18 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f37e0367ad6f2147a0b37564b442b7a25bec0d23, edef1355224c0799a502a46b71d3649fa0dd218e, b38af5386a74416e898955443f2e26547b358cb2 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 208489032bdd8d4a7de50f3057c175058f271956, < f37e0367ad6f2147a0b37564b442b7a25bec0d23	Fixed in f37e0367ad6f2147a0b37564b442b7a25bec0d23
LinuxLinux	Affected ≥ 208489032bdd8d4a7de50f3057c175058f271956, < edef1355224c0799a502a46b71d3649fa0dd218e	Fixed in edef1355224c0799a502a46b71d3649fa0dd218e
LinuxLinux	Affected ≥ 208489032bdd8d4a7de50f3057c175058f271956, < b38af5386a74416e898955443f2e26547b358cb2	Fixed in b38af5386a74416e898955443f2e26547b358cb2
LinuxLinux	Affected ≥ 208489032bdd8d4a7de50f3057c175058f271956, < 46e75703ca3f00fb8c935b3ce35b90836e34e8af	Fixed in 46e75703ca3f00fb8c935b3ce35b90836e34e8af
LinuxLinux	Affected ≥ 208489032bdd8d4a7de50f3057c175058f271956, < 9e799f25c420e759641eb25102967ea091fc758f	Fixed in 9e799f25c420e759641eb25102967ea091fc758f
LinuxLinux	Affected =4.2	Fixed in–

AI-suggested

Apply the official fix that calls cancel_delayed_work_sync() after mmc_remove_host() to ensure proper synchronization and prevent use-after-free. This fix is included in the identified fixed commits. No additional mitigation is required once the patch is applied.

Description

A use-after-free vulnerability in the Linux kernel's mtk-sd MMC driver was fixed by ensuring that the request timeout work is properly canceled on driver removal. The flaw involved a race condition where a timeout callback could access freed host resources, leading to potential memory corruption.

Impact

The vulnerability causes use-after-free memory access during driver unbind, which can lead to kernel memory corruption and potential system instability or crashes. No known exploits in the wild have been reported.

Summary

The Linux kernel's mtk-sd MMC driver queued a request timeout work while a request was active. The function msdc_request_done() used cancel_delayed_work(), which does not wait for a timeout callback already in progress. This callback calls mmc_request_done(), which accesses host resources that may have been freed during driver unbind in msdc_drv_remove(). This led to use-after-free conditions detected by KASAN in unbind tests. The fix involves calling cancel_delayed_work_sync() after mmc_remove_host() to ensure the timeout callback completes before releasing host resources.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:58 UTC

Technical details

References

Community reviews

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