ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 1 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free The previous commit 0718a78f6a9f ("ALSA: usb-audio: Kill timer properly at removal") patched a UAF issue caused by the error timer. However, because the error timer kill added in this patch occurs after the endpoint delete, a race condition to UAF still occurs, albeit rarely. Additionally, since kill-cleanup for urb is also missing, freed memory can be accessed in interrupt context related to urb, which can cause UAF. Therefore, to prevent this, error timer and urb must be killed before freeing the heap memory.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.175, 6.16
- Fix · CNA Linux (Linux) Fixed in 6.1.175, 6.16.11, 6.17.1, 6.18
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2025-39997
- 2026-10-03 Alias added: GHSA-xc3r-7j5x-74w4
References
Other 7
- https://git.kernel.org/stable/c/e63f049c7764b615d1d50cb486745fa63372b42d
- https://git.kernel.org/stable/c/e16985513e89466a236d2a7c202783b4dd0c5a46
- https://git.kernel.org/stable/c/dc4874366cf6cf4a31d8fa4b7f0e2a5b2d7647ba
- https://git.kernel.org/stable/c/647d6b8d22be12842fde6ed0c56859ebc615f21e
- https://git.kernel.org/stable/c/af600e7f5526d16146b3ae99f6ad57bfea79ca33
- https://git.kernel.org/stable/c/353d8c715cc951a980728133c9dd64ca5a0a186c
- https://git.kernel.org/stable/c/9f2c0ac1423d5f267e7f1d1940780fc764b0fee3
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Sources
- CVE-2025-39997 · CVE Program
- CVE-2025-39997 · NVD
- FIRST EPSS
- GHSA-xc3r-7j5x-74w4 · GitHub Advisory Database · CC BY 4.0
- CVE-2025-39997 · Red Hat security data · CC BY 4.0
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