CVE-2026-80971: Linux kernel · ALSA: bcd2000: clear the URB pointers on disconnect
Source GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: bcd2000: clear the URB pointers on disconnect bcd2000_free_usb_related_resources() frees both URBs and leaves the pointers behind: usb_kill_urb(bcd2k->midi_out_urb); usb_kill_urb(bcd2k->midi_in_urb); usb_free_urb(bcd2k->midi_out_urb); usb_free_urb(bcd2k->midi_in_urb); The rawmidi device outlives that call. A substream that is still open when the device is unplugged reaches bcd2000_midi_send() from the trigger path on close. That function writes to the freed URB and then hands it to the USB core: bcd2k->midi_out_urb->transfer_buffer_length = BUFSIZE; ... ret = usb_submit_urb(bcd2k->midi_out_urb, GFP_ATOMIC); usb_kill_urb() does not stop a later submission either, so a submit that races the disconnect can requeue the URB after it has been reaped. midi_in_urb is exposed the same way: bcd2000_input_complete() resubmits it from the completion handler. KASAN on 7.2.0-rc5 (arm64): BUG: KASAN: slab-use-after-free in bcd2000_midi_send [snd_bcd2000] Write of size 4 at addr ffff00001827d388 by task bpoc/168 __asan_store4 bcd2000_midi_send [snd_bcd2000] bcd2000_midi_output_trigger [snd_bcd2000] snd_rawmidi_kernel_write1 close_substream.part.0 Freed by task 168: usb_free_urb bcd2000_disconnect [snd_bcd2000] BUG: KASAN: slab-use-after-free in usb_submit_urb Read of size 8 at addr ffff00001827d3b8 by task bpoc/168 Clear both pointers after freeing and test them on the paths that can still run. Poison the URBs before freeing them: usb_poison_urb() waits for a running completion handler and rejects any later submission, so after it returns the input path is quiesced and only the rawmidi trigger path can still reach bcd2000_midi_send(). No unpoison is needed; the URBs are freed on the next line. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>
References
- nvd.nist.gov/vuln/detail/CVE-2026-80971 (opens in a new tab)
- git.kernel.org/stable/c/3c00004f134fc819f9d9e202c6a64acde0a1f8d0 (opens in a new tab)
- git.kernel.org/stable/c/459d3a64766f5ca2f1886daeaf24582831a5f5ab (opens in a new tab)
- git.kernel.org/stable/c/5a77febac6faf6da40fbb4555f703eeb91b58130 (opens in a new tab)
- git.kernel.org/stable/c/6c07aad8a7c9ef8ebc4d03a964b882123a349a2e (opens in a new tab)
- git.kernel.org/stable/c/7df3194bdb7479cad9199889655a566a2c0c1d1b (opens in a new tab)
- git.kernel.org/stable/c/9af08677aa57debaca5b57c8045c52a83d3dd376 (opens in a new tab)
- git.kernel.org/stable/c/b06ebc7fe25a6af4a9f6e4a3d4236a4178ad4b01 (opens in a new tab)
- git.kernel.org/stable/c/eb482a06791d6168beb8c78cc904ac5a5ed96a55 (opens in a new tab)