--- id: CVE-2026-80971 title: 'ALSA: bcd2000: clear the URB pointers on disconnect' summary: "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: bcd2000: clear the URB pointers on disconnect\n\nbcd2000_free_usb_related_resources() frees both URBs and leaves the\npointers behind:\n\n\tusb_kill_urb(bcd2k->midi_out…" severity: high cvss: 7.8 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H' cvssSource: cna cwe: - CWE-825 vendor: Linux product: Linux affected: - >- Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 9af08677aa57debaca5b57c8045c52a83d3dd376 - >- Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 5a77febac6faf6da40fbb4555f703eeb91b58130 - >- Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 3c00004f134fc819f9d9e202c6a64acde0a1f8d0 - >- Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 6c07aad8a7c9ef8ebc4d03a964b882123a349a2e - >- Linux >= b47a22290d581277be70e8a597824a4985d39e83 < eb482a06791d6168beb8c78cc904ac5a5ed96a55 - >- Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 7df3194bdb7479cad9199889655a566a2c0c1d1b - >- Linux >= b47a22290d581277be70e8a597824a4985d39e83 < b06ebc7fe25a6af4a9f6e4a3d4236a4178ad4b01 - >- Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 459d3a64766f5ca2f1886daeaf24582831a5f5ab - Linux 3.16 ssvc: exploitation: none automatable: 'no' technicalImpact: total timestamp: '2026-10-16T19:21:35.341329Z' published: '2026-09-11' updated: '2026-10-19' sourceUpdated: '2026-10-19T08:45:55.974Z' source: CVEORG sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80971' references: - url: 'https://git.kernel.org/stable/c/9af08677aa57debaca5b57c8045c52a83d3dd376' - url: 'https://git.kernel.org/stable/c/5a77febac6faf6da40fbb4555f703eeb91b58130' - url: 'https://git.kernel.org/stable/c/3c00004f134fc819f9d9e202c6a64acde0a1f8d0' - url: 'https://git.kernel.org/stable/c/6c07aad8a7c9ef8ebc4d03a964b882123a349a2e' - url: 'https://git.kernel.org/stable/c/eb482a06791d6168beb8c78cc904ac5a5ed96a55' - url: 'https://git.kernel.org/stable/c/7df3194bdb7479cad9199889655a566a2c0c1d1b' - url: 'https://git.kernel.org/stable/c/b06ebc7fe25a6af4a9f6e4a3d4236a4178ad4b01' - url: 'https://git.kernel.org/stable/c/459d3a64766f5ca2f1886daeaf24582831a5f5ab' - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80971.json - url: 'https://access.redhat.com/security/cve/CVE-2026-80971' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532082' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-80971' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80971' - url: >- https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80971.mbox tags: - cve.org - csaf - vex - red-hat epss: 0.00164 epssPercentile: 0.05555 scores: cna: 7.8 vendor: 7 ingestedAt: '2026-09-14T15:23:07.455Z' --- ## Overview 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 ## Affected - `Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 9af08677aa57debaca5b57c8045c52a83d3dd376` - `Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 5a77febac6faf6da40fbb4555f703eeb91b58130` - `Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 3c00004f134fc819f9d9e202c6a64acde0a1f8d0` - `Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 6c07aad8a7c9ef8ebc4d03a964b882123a349a2e` - `Linux >= b47a22290d581277be70e8a597824a4985d39e83 < eb482a06791d6168beb8c78cc904ac5a5ed96a55` - `Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 7df3194bdb7479cad9199889655a566a2c0c1d1b` - `Linux >= b47a22290d581277be70e8a597824a4985d39e83 < b06ebc7fe25a6af4a9f6e4a3d4236a4178ad4b01` - `Linux >= b47a22290d581277be70e8a597824a4985d39e83 < 459d3a64766f5ca2f1886daeaf24582831a5f5ab` - `Linux 3.16` ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **Red Hat VEX** · Moderate · affected: 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, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80971.json)