CVE-2026-74682ALSA: usb-audio: fix OOB write on Type II inbound URBs
- —Not scoredno CVSS score yet
- 0.18%Exploitation in 30 daysEPSS · top 93% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: fix OOB write on Type II inbound URBs data_ep_set_params() sizes each URB transfer buffer before it adds the Format Type II transfer delimiter: u->packets = urb_packs; u->buffer_size = maxsize * u->packets; if (fmt->fmt_type == UAC_FORMAT_TYPE_II) u->packets++; /* for transfer delimiter */ u->urb = usb_alloc_urb(u->packets, GFP_KERNEL); buffer_size is computed from the pre-increment packet count and never recomputed, so for a Type II endpoint the buffer is one packet short of the packet count the URB is built with. prepare_inbound_urb() then lays out one iso frame per packet and never consults buffer_size: offs = 0; for (i = 0; i < urb_ctx->packets; i++) { urb->iso_frame_desc[i].offset = offs; urb->iso_frame_desc[i].length = ep->curpacksize; offs += ep->curpacksize; } urb->transfer_buffer_length = offs; urb->number_of_packets = urb_ctx->packets; The last descriptor therefore points one packet past the end of the transfer buffer, where the host controller writes device data on every inbound transfer. prepare_silent_urb() and prepare_playback_urb() bound their fill loops by ctx->buffer_size, so only capture is affected. fmt_type comes from the device's audio streaming descriptors, so any device advertising a Type II capture format hits this once userspace sets hw_params on the stream. KASAN on 7.2.0-rc5 (arm64) with a dummy_hcd/raw-gadget device, one report per inbound transfer: BUG: KASAN: slab-out-of-bounds in dummy_timer Write of size 64 at addr ffff0000186171c0 by task cons02/166 __asan_memcpy dummy_timer hrtimer_run_softirq Allocated by task 166: usb_alloc_coherent snd_usb_endpoint_set_params The buggy address is located 0 bytes to the right of allocated 64-byte region [ffff000018617180, ffff0000186171c0) Compute buffer_size after the delimiter packet has been accounted for, and bound the fill loop by buffer_size, as prepare_silent_urb() already does on the outbound side. This grows every Type II URB allocation by one maxsize packet. Discovered by XBOW, triaged by Baul Lee <[email protected]>
Timeline
ID reserved
By Linux
- 7 days later
· 7 days later
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.18% · top 93% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 8fdff6a319e7dac757c558bd283dc4577e68cde7 – < 6af5f29af7711233ae68d3b25c15d67478468900
- affected 8fdff6a319e7dac757c558bd283dc4577e68cde7 – < f1fbb50b99311b35c2e85cc70341d62082dca4b5
- affected 8fdff6a319e7dac757c558bd283dc4577e68cde7 – < 137bf034740e5a2734794908d0aff1e0bd7cee6e
- affected 8fdff6a319e7dac757c558bd283dc4577e68cde7 – < 6607f85242577f33d4540a0d1f4a6137f5367058
- affected 8fdff6a319e7dac757c558bd283dc4577e68cde7 – < ca22c94bdfc22c564ca2e11c87ba4d17ebeaaa9a
- affected 8fdff6a319e7dac757c558bd283dc4577e68cde7 – < 0a235379825e1a6194e43861ee6658e5fc35686d
- affected 8fdff6a319e7dac757c558bd283dc4577e68cde7 – < d3ed4e6321bb453757044cb9e5ecb30a33f04903
- affected 8fdff6a319e7dac757c558bd283dc4577e68cde7 – < 69ee44e1a23be62318189dc4b37fa4ad94053269
- affected 3.5
- unaffected < 3.5
- unaffected 5.10.265 – ≤ 5.10.*
- unaffected 5.15.216 – ≤ 5.15.*
- unaffected 6.1.183 – ≤ 6.1.*
- unaffected 6.6.152 – ≤ 6.6.*
- unaffected 6.12.104 – ≤ 6.12.*
- unaffected 6.18.45 – ≤ 6.18.*
- unaffected 7.1.9 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References8
- https://git.kernel.org/stable/c/6af5f29af7711233ae68d3b25c15d67478468900 (opens in a new tab)
- https://git.kernel.org/stable/c/f1fbb50b99311b35c2e85cc70341d62082dca4b5 (opens in a new tab)
- https://git.kernel.org/stable/c/137bf034740e5a2734794908d0aff1e0bd7cee6e (opens in a new tab)
- https://git.kernel.org/stable/c/6607f85242577f33d4540a0d1f4a6137f5367058 (opens in a new tab)
- https://git.kernel.org/stable/c/ca22c94bdfc22c564ca2e11c87ba4d17ebeaaa9a (opens in a new tab)
- https://git.kernel.org/stable/c/0a235379825e1a6194e43861ee6658e5fc35686d (opens in a new tab)
- https://git.kernel.org/stable/c/d3ed4e6321bb453757044cb9e5ecb30a33f04903 (opens in a new tab)
- https://git.kernel.org/stable/c/69ee44e1a23be62318189dc4b37fa4ad94053269 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-64369 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-74682)Record last updated .