VulnerabilityPublished 15 Aug 2026Updated 21 Oct 2026

CVE-2026-72073: Linux kernel · mmc: vub300: fix use-after-free on probe failure

Affects Linux kernelSource GCVE Database

Authoritative record:CVE-2026-72073

Not known to be exploited · fixed in 7.0.0-1014.14~24.04.1 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 7.0.0-1014.14~24.04.1, 7.0.0-1017.17~24.04.1, 7.0.0-1016.16~24.04.1 +11

Exploitation evidence

Disclosed: evidence found.
CVE published 15 Aug 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.

ghsa-2w4f-22fv-v9w4

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected <7.0.0-38.38	Fixed in 7.0.0-38.38
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected <7.0.0-1014.14	Fixed in 7.0.0-1014.14
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected <7.0.0-1017.17	Fixed in 7.0.0-1017.17
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected <7.0.0-1016.16	Fixed in 7.0.0-1016.16
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected <7.0.0-1014.14	Fixed in 7.0.0-1014.14
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected <7.0.0-1008.9	Fixed in 7.0.0-1008.9

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and should be applied to affected Linux Azure kernel versions. The fix corrects the reference counting and cleanup logic to prevent the use-after-free condition. Users should update to the fixed kernel versions as provided by their Linux distribution or vendor. No additional mitigation is required beyond applying the official fix.

Description

A use-after-free vulnerability was identified and fixed in the Linux kernel's vub300 MMC driver used in Linux Azure kernels. The flaw occurs on probe failure due to improper lifetime management of the controller state, leading to a race condition between the inactivity timer and error handling paths. This can cause the driver to access freed memory, though exploitation is unlikely in practice due to timing constraints. The issue has been addressed by correcting the reference counting and cleanup logic to prevent use-after-free.

Impact

This vulnerability could lead to a use-after-free condition in the vub300 MMC driver on Linux Azure kernels, potentially causing system instability or crashes. However, exploitation is unlikely in practice because it requires the mmc_add_host() function to fail and take more than one second, which is rare. There are no known exploits in the wild. The impact is limited to affected Linux Azure kernel versions running the vulnerable driver.

Summary

The Linux kernel vub300 MMC driver improperly manages its controller state lifetime using reference counting (kref). On probe failure, a race condition exists between the inactivity timer firing and the error path that frees the MMC host directly, bypassing proper reference release. Specifically, timer_delete_sync() only waits for the timer callback but does not wait for any deadwork queued by the callback, which can still hold references. This leads to a use-after-free condition when the probe error path frees the backing MMC host while deadwork still holds references. The fix involves clearing the interface pointer so that timer callbacks and deadwork return early and drop references, and dropping the initial probe reference without freeing the host prematurely.

References

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