CVE-2022-49686
Published: 26 February 2025
Summary
CVE-2022-49686 is a high-severity Double Free (CWE-415) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 24.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 RA-5 (Vulnerability Monitoring and Scanning) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2022-49686 is a vulnerability in the Linux kernel's USB gadget UVC (USB Video Class) driver, specifically within the uvcg_video_pump function. It arises from a list double-add error where a USB request is added back to the req_free list after already being queued to an endpoint, particularly when the endpoint becomes disabled. This triggers a kernel panic due to list debug checks failing, as evidenced by kernel logs showing a BUG at lib/list_debug.c:31 during uvc_function_set_alt execution. The issue is classified under CWE-415 (Double Free) with a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
A local attacker with low privileges (PR:L) can exploit this vulnerability by interacting with the USB gadget UVC configuration, such as disabling an endpoint during video pump operations. This leads to the double addition of a request to the req_free list—once by the endpoint completion handler and again by uvcg_video_pump—resulting in a detected list corruption and immediate kernel panic. The attacker achieves denial of service through system crash, with high impacts on confidentiality, integrity, and availability due to the kernel-level disruption.
Mitigation involves applying the upstream kernel patches referenced in the stable commit logs. The fix invalidates the local request handle after queuing to prevent re-addition to the req_free list, as implemented in commits like 96163f835e65 (stable queue) and d95ac8b920de (related stable update). Security practitioners should update affected Linux kernels to versions incorporating these changes.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2022-54547
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: uvc: fix list double add in uvcg_video_pump A panic can occur if the endpoint becomes disabled and the uvcg_video_pump adds the request back to the req_free list after…
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it has already been queued to the endpoint. The endpoint complete will add the request back to the req_free list. Invalidate the local request handle once it's been queued. <6>[ 246.796704][T13726] configfs-gadget gadget: uvc: uvc_function_set_alt(1, 0) <3>[ 246.797078][ T26] list_add double add: new=ffffff878bee5c40, prev=ffffff878bee5c40, next=ffffff878b0f0a90. <6>[ 246.797213][ T26] ------------[ cut here ]------------ <2>[ 246.797224][ T26] kernel BUG at lib/list_debug.c:31! <6>[ 246.807073][ T26] Call trace: <6>[ 246.807180][ T26] uvcg_video_pump+0x364/0x38c <6>[ 246.807366][ T26] process_one_work+0x2a4/0x544 <6>[ 246.807394][ T26] worker_thread+0x350/0x784 <6>[ 246.807442][ T26] kthread+0x2ac/0x320
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local kernel flaw enables deliberate system crash via crafted USB gadget interaction, directly supporting Endpoint DoS through application/system exploitation.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
SI-2 requires timely identification, reporting, and correction of system flaws, directly mitigating CVE-2022-49686 by applying Linux kernel patches that invalidate the request handle after queuing.
RA-5 mandates vulnerability scanning to identify known issues like this Linux kernel USB gadget UVC driver flaw in deployed systems.
CM-7 enforces least functionality by disabling unnecessary capabilities such as the USB UVC gadget driver, preventing exploitation opportunities.