usb: gadget: f_fs: Prevent race during ffs_ep0_queue_wait
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-416 and the CVSS impact.
Summary
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Prevent race during ffs_ep0_queue_wait While performing fast composition switch, there is a possibility that the process of ffs_ep0_write/ffs_ep0_read get into a race condition due to ep0req being freed up from functionfs_unbind. Consider the scenario that the ffs_ep0_write calls the ffs_ep0_queue_wait by taking a lock &ffs->ev.waitq.lock. However, the functionfs_unbind isn't bounded so it can go ahead and mark the ep0req to NULL, and since there is no NULL check in ffs_ep0_queue_wait we will end up in use-after-free. Fix this by making a serialized execution between the two functions using a mutex_lock(ffs->mutex).
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.35 and later | 4.14.305, 4.19.272, 5.4.231, 5.10.166, 5.15.91, 6.1.9, 6.2 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.35 and later Fixed in 4.14.305, 4.19.272, 5.4.231, 5.10.166, 5.15.91, 6.1.9, 6.2 Patch available CNA
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 2.6.35 to before 4.14.305; 4.15 to before 4.19.272; 4.20 to before 5.4.231; 5.5 to before 5.10.166; 5.11 to before 5.15.91; 5.16 to before 6.1.9 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.2:rc1:*:*:*:*:*:* | 6.2 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.2:rc2:*:*:*:*:*:* | 6.2 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.2:rc3:*:*:*:*:*:* | 6.2 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.2:rc4:*:*:*:*:*:* | 6.2 rc4 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 2.6.35 to before 4.14.305; 4.15 to before 4.19.272; 4.20 to before 5.4.231; 5.5 to before 5.10.166; 5.11 to before 5.15.91; 5.16 to before 6.1.9 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.2:rc1:*:*:*:*:*:* Versions 6.2 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.2:rc2:*:*:*:*:*:* Versions 6.2 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.2:rc3:*:*:*:*:*:* Versions 6.2 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.2:rc4:*:*:*:*:*:* Versions 6.2 rc4 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.14.305, 4.19.272, 5.4.231, 5.10.166, 5.15.91, 6.1.9, 6.2
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
Not affected: 5 products
- Red Hat Enterprise Linux 10
- 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-2022-49755
- 2026-10-03 Alias added: GHSA-qc5x-h4r4-86f3
References
Patch 7
- https://git.kernel.org/stable/c/facf353c9e8d7885b686d9a4b173d4e0af6441d2
- https://git.kernel.org/stable/c/e9036e951f93fb8d7b5e9d6e2c7f94a4da312ae4
- https://git.kernel.org/stable/c/a8d40942df074f4ebcb9bd3413596d92f323b064
- https://git.kernel.org/stable/c/6dd9ea05534f323668db94fcc2726c7a84547e78
- https://git.kernel.org/stable/c/ae8e136bcaae96163b5821984de1036efc9abb1a
- https://git.kernel.org/stable/c/6aee197b7fbcd61596a78b47d553f2f99111f217
- https://git.kernel.org/stable/c/6a19da111057f69214b97c62fb0ac59023970850
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Sources
- CVE-2022-49755 · CVE Program
- CVE-2022-49755 · NVD
- FIRST EPSS
- GHSA-qc5x-h4r4-86f3 · GitHub Advisory Database · CC BY 4.0
- CVE-2022-49755 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences