CVE-2026-72073: Linux Vulnerability

Description

In the Linux kernel, the following vulnerability has been resolved: mmc: vub300: fix use-after-free on probe failure The vub300 driver lifetime-manages its controller state using vub300->kref, with vub300_delete() freeing the mmc host when the last reference is dropped. The probe error path after the inactivity timer has been armed still bypasses that lifetime rule, however, and falls through to mmc_free_host() directly if mmc_add_host() fails. The race window is between arming the inactivity timer and reaching the probe error unwind after mmc_add_host() fails: probe thread timer/workqueue ------------ --------------- kref_init(&vub300->kref) ref = 1 kref_get(&vub300->kref) ref = 2, timer ref add_timer(inactivity_timer) fires after one second | | race window |<----------------------------------------------------> | mmc_add_host(mmc) inactivity timer fires vub300_queue_dead_work() kref_get() ref = 3 queue_work(deadwork) mmc_add_host() fails timer_delete_sync() mmc_free_host(mmc) frees vub300 deadwork runs use-after-free The inactivity timeout is one second, so this would require mmc_add_host() to both fail and take more than one second to do so. This is unlikely to happen in practice, but the error path is still wrong. timer_delete_sync() only waits for the timer callback itself. It does not flush deadwork that the callback may already have queued. As a result, queued deadwork can still hold a kref while the probe error path directly frees the backing mmc host, including the vub300 storage. Fix this by using the same lifetime mechanism as disconnect. Clear vub300->interface so that the timer callback and any queued deadwork return early and drop their references, then drop the initial probe reference and return without falling through to err_free_host.

Metrics

EPSS Probability

0.22%

12.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 0613ad2401f88bdeae5594c30afe318e93b14676, < 5b82af744e06cd741938c3da54fdbe564a7e52d9; >= 0613ad2401f88bdeae5594c30afe318e93b14676, < 618cf6b139503ec18ef93ffd663396aaf99b763a; >= 0613ad2401f88bdeae5594c30afe318e93b14676, < a3b5f242997a3be7404112fd48784881560aea57; 41ed46bdbd2878cd6567abe0974a445f8b1b8ec8; 25f05d762ca5e1c685002a53dd44f68e78ca3feb; a46e681151bbdacdf6b89ee8c4e5bad0555142bb; 3b29f8769d32016b2d89183db4d80c7a71b7e35e; 3049a3b927a40d89d4582ff1033cd7953be773c7; afc898019e7bf18c5eb7a0ac19852fcb1b341b3c; c9e85979b59cb86f0a15defa8199d740e2b36b90; 2044b2ea77945f372ef161d1bbf814e471767ff2; >= 4.9.337, < 4.10; >= 4.14.303, < 4.15; >= 4.19.270, < 4.20; >= 5.4.229, < 5.5; >= 5.10.163, < 5.11; >= 5.15.86, < 5.16; >= 6.0.16, < 6.1; >= 6.1.2, < 6.2
Linux	Linux	6.2

References

Timeline

Published: Aug 15, 2026
Last Modified: Aug 17, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-72073?

In the Linux kernel, the following vulnerability has been resolved: mmc: vub300: fix use-after-free on probe failure The vub300 driver lifetime-manages its controller state using vub300->kref, with vub300_delete() freeing the mmc host when the last reference is dropped. The probe error path after the inactivity timer has been armed still bypasses that lifetime rule, however, and falls through to mmc_free_host() directly if mmc_add_host() fails. The race window is between arming the inactivity timer and reaching the probe error unwind after mmc_add_host() fails: probe thread timer/workqueue ------------ --------------- kref_init(&vub300->kref) ref = 1 kref_get(&vub300->kref) ref = 2, timer ref add_timer(inactivity_timer) fires after one second | | race window |<----------------------------------------------------> | mmc_add_host(mmc) inactivity timer fires vub300_queue_dead_work() kref_get() ref = 3 queue_work(deadwork) mmc_add_host() fails timer_delete_sync() mmc_free_host(mmc) frees vub300 deadwork runs use-after-free The inactivity timeout is one second, so this would require mmc_add_host() to both fail and take more than one second to do so. This is unlikely to happen in practice, but the error path is still wrong. timer_delete_sync() only waits for the timer callback itself. It does not flush deadwork that the callback may already have queued. As a result, queued deadwork can still hold a kref while the probe error path directly frees the backing mmc host, including the vub300 storage. Fix this by using the same lifetime mechanism as disconnect. Clear vub300->interface so that the timer callback and any queued deadwork return early and drop their references, then drop the initial probe reference and return without falling through to err_free_host.

How severe is CVE-2026-72073?

Severity scoring for CVE-2026-72073 is pending analysis. The EPSS model estimates a 0.22% probability of exploitation in the next 30 days.

How do I fix CVE-2026-72073?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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