ALSA: bcd2000: clear the URB pointers on disconnect

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 <[email protected]>

Timeline

Scores

EPSS (exploitation in 30 days)

0.16% · top 94% of all CVEs (12 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.

Affected products

• Linux · Linux

  • affected b47a22290d581277be70e8a597824a4985d39e83 – < 9af08677aa57debaca5b57c8045c52a83d3dd376
  • affected b47a22290d581277be70e8a597824a4985d39e83 – < 5a77febac6faf6da40fbb4555f703eeb91b58130
  • affected b47a22290d581277be70e8a597824a4985d39e83 – < 3c00004f134fc819f9d9e202c6a64acde0a1f8d0
  • affected b47a22290d581277be70e8a597824a4985d39e83 – < 6c07aad8a7c9ef8ebc4d03a964b882123a349a2e
  • affected b47a22290d581277be70e8a597824a4985d39e83 – < eb482a06791d6168beb8c78cc904ac5a5ed96a55
  • affected b47a22290d581277be70e8a597824a4985d39e83 – < 7df3194bdb7479cad9199889655a566a2c0c1d1b
  • affected b47a22290d581277be70e8a597824a4985d39e83 – < b06ebc7fe25a6af4a9f6e4a3d4236a4178ad4b01
  • affected b47a22290d581277be70e8a597824a4985d39e83 – < 459d3a64766f5ca2f1886daeaf24582831a5f5ab

• Linux · Linux

  • affected 3.16
  • unaffected < 3.16
  • unaffected 5.10.270 – ≤ 5.10.*
  • unaffected 5.15.221 – ≤ 5.15.*
  • unaffected 6.1.188 – ≤ 6.1.*
  • unaffected 6.6.157 – ≤ 6.6.*
  • unaffected 6.12.109 – ≤ 6.12.*
  • unaffected 6.18.50 – ≤ 6.18.*
  • unaffected 7.2.4 – ≤ 7.2.*
  • unaffected 7.3 – ≤ *

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-2026-76294 (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)

Badge for a README or a ticket

[![CVE-2026-80971](https://cveledger.app/badge/CVE-2026-80971.svg)](https://cveledger.app/cve/CVE-2026-80971)

Record last updated 19 Oct 2026, 08:45 UTC.