CVE-2025-40223 — most: usb: Fix use-after-free in hdm_disconnect
In the Linux kernel, the following vulnerability has been resolved: most: usb: Fix use-after-free in hdm_disconnect hdm_disconnect() calls most_deregister_interface(), which eventually unregisters the MOST interface device with device_unregister(iface->dev). If that drops the last reference, the device core may call release_mdev() immediately while hdm_disconnect() is still executing. The old code also freed several mdev-owned allocations in hdm_disconnect() and then performed additional put_device() calls. Depending on refcount order, this could lead to use-after-free or double-free when release_mdev() ran (or when unregister paths also performed puts). Fix by moving the frees of mdev-owned allocations into release_mdev(), so they happen exactly once when the device is truly released, and by dropping the extra put_device() calls in hdm_disconnect() that are redundant after device_unregister() and most_deregister_interface(). This addresses the KASAN slab-use-after-free reported by syzbot in hdm_disconnect(). See report and stack traces in the bug link below.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+2
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux | ≥ 97a6f772f36b7f52bcfa56a581bbd2470cffe23d and < 5b5c478f09b1b35e7fe6fc9a1786c9bf6030e831≥ 97a6f772f36b7f52bcfa56a581bbd2470cffe23d and < 578eb18cd111addec94c43f61cd4b4429e454809≥ 97a6f772f36b7f52bcfa56a581bbd2470cffe23d and < 33daf469f5294b9d07c4fc98216cace9f4f34cc6≥ 97a6f772f36b7f52bcfa56a581bbd2470cffe23d and < 72427dc6f87523995f4e6ae35a948bb2992cabce≥ 97a6f772f36b7f52bcfa56a581bbd2470cffe23d and < f93a84ffb884d761a9d4e869ba29c238711e81f1≥ 97a6f772f36b7f52bcfa56a581bbd2470cffe23d and < 3a3b8e89c7201c5b3b76ac4a4069d1adde1477d6≥ 97a6f772f36b7f52bcfa56a581bbd2470cffe23d and < 4b1270902609ef0d935ed2faa2ea6d122bd148f5version 5.9 | Vulnerable | CVE Program (cve.org) e CISA ADP |
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.21%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Not enough vector or weakness data: use the affected application’s logs as a starting point.
Timeline
What happened to this CVE, newest first.
- 2026
- Record published
- Affected products added · linux/linux
- Source status changed · → Deferred
- Record created in this database
- 2025
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
7 on the record
- git.kernel.org/stable/c/33daf469f5294b9d07c4fc98216cace9f4f34cc6
- git.kernel.org/stable/c/4b1270902609ef0d935ed2faa2ea6d122bd148f5
- git.kernel.org/stable/c/578eb18cd111addec94c43f61cd4b4429e454809
- git.kernel.org/stable/c/72427dc6f87523995f4e6ae35a948bb2992cabce
- git.kernel.org/stable/c/3a3b8e89c7201c5b3b76ac4a4069d1adde1477d6
- git.kernel.org/stable/c/5b5c478f09b1b35e7fe6fc9a1786c9bf6030e831
- git.kernel.org/stable/c/f93a84ffb884d761a9d4e869ba29c238711e81f1
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 13h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 13h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CVSS score published by NVD, the CNA, CISA or GitHub so far.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2025-40223 is "most: usb: Fix use-after-free in hdm_disconnect", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.21% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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