CVE-2026-98312 - Vulnerability Details

- ALSA: 6fire: fix OOB write from device-reported iso length

Description

In the Linux kernel, the following vulnerability has been resolved:

ALSA: 6fire: fix OOB write from device-reported iso length

usb6fire_pcm_in_urb_handler() sizes each outgoing isochronous packet as
(actual_length - 4) / (in_n_analog << 2) * (out_n_analog << 2) + 4, where
actual_length is the unsigned length the device reported for the matching
IN packet. A packet completed with status 0 and actual_length < 4 wraps
the subtraction to 0x7fffffec; a zero-length isochronous packet is legal
on the bus, and the preceding loop rejects only non-zero status. The sum
reaches memset() on out_urb->buffer, a 4832-byte object from
kcalloc(PCM_MAX_PACKET_SIZE, PCM_N_PACKETS_PER_URB).

Even without the wrap the result is out of bounds: at 88.2/96 kHz the
4-in/6-out scaling turns a full 420-byte IN packet into 628, so eight
packets span 5024 bytes of that buffer. usb_submit_urb() rejects an
over-long descriptor only after the memset() and the
usb6fire_pcm_playback() copy of user PCM data have run.

Guard the subtraction as the sibling usb6fire_pcm_capture() already does,
and limit the frame count to what fits in rt->out_packet_size, the OUT
endpoint's wMaxPacketSize. This bounds total_length by the buffer size
while keeping each packet length aligned to a whole output frame.

BUG: KASAN: out-of-bounds in usb6fire_pcm_in_urb_handler (sound/usb/6fire/pcm.c:338)
Write of size 18446744073709551456 at addr ffff88802a3d0000 by task vhci_rx/5018
Call Trace:
dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)
print_report (mm/kasan/report.c:378 mm/kasan/report.c:482)
kasan_report (mm/kasan/report.c:595)
kasan_check_range (mm/kasan/generic.c:186 mm/kasan/generic.c:200)
__asan_memset (mm/kasan/shadow.c:84)
usb6fire_pcm_in_urb_handler (sound/usb/6fire/pcm.c:338)
__usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1657)
usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1741)
vhci_rx_loop (drivers/usb/usbip/vhci_rx.c:107 drivers/usb/usbip/vhci_rx.c:242)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245)

Allocated by task 10:
__kmalloc_cache_noprof (mm/slub.c:5563)
usb6fire_pcm_init (sound/usb/6fire/pcm.c:560 sound/usb/6fire/pcm.c:595)
usb6fire_chip_probe (sound/usb/6fire/chip.c:133)
usb_probe_interface (drivers/usb/core/driver.c:399)

The buggy address belongs to the object at ffff88802a3d0000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 0 bytes inside of
4832-byte region [ffff88802a3d0000, ffff88802a3d12e0)
Kernel panic - not syncing: Fatal exception in interrupt

Published: 2026-10-06

Score: 7.0 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

In the ALSA 6fire driver, an incorrect calculation of packet sizes allows a buffer overrun during isochronous PCM playback. The bug causes an out‑of‑bounds write into a 4832‑byte kernel buffer, which can lead to memory corruption, system instability, or a kernel panic. The vulnerability involves data processing from a USB audio device and could subvert kernel integrity by overwriting critical memory structures.

Affected Systems

Any Linux kernel that includes the ALSA 6fire driver is potentially affected. The specific kernel versions are not listed in the advisory; however, any build using the 6fire driver code path targeted by the patch is at risk.

Risk and Exploitability

The CVSS score of 7.0 indicates a medium to high severity attack potential. The EPSS score remains <1%, signifying a very low, but non‑zero, probability of exploitation. The vulnerability is not catalogued in the CISA KEV database, so no known exploited instances exist. Kernel buffer overrun flaws such as this can lead to memory corruption, a kernel panic, or denial‑of‑service, and the bug can be triggered by a USB device that supplies malformed isochronous packets, making it a local privilege escalation or denial‑of‑service threat.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`c6d43ba816d1cf1d125bfbfc938f2a28a87facf9`	affected	< 61e665fb48e9eee44ec6d610514af383b1802cc1
`c6d43ba816d1cf1d125bfbfc938f2a28a87facf9`	affected	< 246de677552fe5dede293a1543b632e9853f31e4
`c6d43ba816d1cf1d125bfbfc938f2a28a87facf9`	affected	< 001ba7c1d9677225a5ecbc3e60d4865c08bb21d8
`c6d43ba816d1cf1d125bfbfc938f2a28a87facf9`	affected	< ea11ade10583cc45af515d6b24510dbfa0184ca6
`c6d43ba816d1cf1d125bfbfc938f2a28a87facf9`	affected	< cdc31537012bc7a58c95c6750db321b69dd802bb
`c6d43ba816d1cf1d125bfbfc938f2a28a87facf9`	affected	< 1589afe2d099d3e817873bc474676968d7080410

Linux

affected

Version	Status	Constraints
`2.6.39`	affected	—
`0`	unaffected	< 2.6.39
`6.1.189`	unaffected	≤ 6.1.*
`6.6.158`	unaffected	≤ 6.6.*
`6.12.112`	unaffected	≤ 6.12.*
`6.18.54`	unaffected	≤ 6.18.*
`7.2.8`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[c6d43ba816d1cf1d125bfbfc938f2a28a87facf9,61e665fb48e9eee44ec6d610514af383b1802cc1)`	affected	code_commit	—
`[c6d43ba816d1cf1d125bfbfc938f2a28a87facf9,246de677552fe5dede293a1543b632e9853f31e4)`	affected	code_commit	—
`[c6d43ba816d1cf1d125bfbfc938f2a28a87facf9,001ba7c1d9677225a5ecbc3e60d4865c08bb21d8)`	affected	code_commit	—
`[c6d43ba816d1cf1d125bfbfc938f2a28a87facf9,ea11ade10583cc45af515d6b24510dbfa0184ca6)`	affected	code_commit	—
`[c6d43ba816d1cf1d125bfbfc938f2a28a87facf9,cdc31537012bc7a58c95c6750db321b69dd802bb)`	affected	code_commit	—
`[c6d43ba816d1cf1d125bfbfc938f2a28a87facf9,1589afe2d099d3e817873bc474676968d7080410)`	affected	code_commit	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`2.6.39`	affected	semver	—
`[0,2.6.39)`	unaffected	semver	—
`[6.1.189,6.2.0)`	unaffected	semver	—
`[6.6.158,6.7.0)`	unaffected	semver	—
`[6.12.112,6.13.0)`	unaffected	semver	—
`[6.18.54,6.19.0)`	unaffected	semver	—
`[7.2.8,7.3.0)`	unaffected	semver	—
`[7.3-rc4,*]`	unaffected	generic	—

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Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Update the Linux kernel to a version that includes the 6fire driver patch described in the advisory
If immediate kernel updates are not feasible, disable or blacklist the 6fire driver module to stop the vulnerable code from loading
Ensure that any connected USB audio devices are physically secured or removed to prevent an attacker from sending crafted packets to the driver

Generated by OpenCVE AI on October 10, 2026 at 01:57 UTC.

Tracking

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Advisories

Source	ID	Title
Debian DLA	DLA-4841-1	linux security update
Debian DLA	DLA-4850-1	linux-6.12 security update
Debian DSA	DSA-6568-1	linux security update

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00173.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98312.mbox
https://git.kernel.org/stable/c/001ba7c1d9677225a5ecbc3e60d4865c08bb21d8
https://git.kernel.org/stable/c/1589afe2d099d3e817873bc474676968d7080410
https://git.kernel.org/stable/c/246de677552fe5dede293a1543b632e9853f31e4
https://git.kernel.org/stable/c/61e665fb48e9eee44ec6d610514af383b1802cc1
https://git.kernel.org/stable/c/cdc31537012bc7a58c95c6750db321b69dd802bb
https://git.kernel.org/stable/c/ea11ade10583cc45af515d6b24510dbfa0184ca6
https://nvd.nist.gov/vuln/detail/CVE-2026-98312
https://www.cve.org/CVERecord?id=CVE-2026-98312

History

Sat, 10 Oct 2026 00:30:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-787
References		https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98312.mbox https://nvd.nist.gov/vuln/detail/CVE-2026-98312 https://www.cve.org/CVERecord?id=CVE-2026-98312
Metrics	threat_severity `None`	cvssV3_1 `{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}` threat_severity `Moderate`

Tue, 06 Oct 2026 18:00:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-119 CWE-122

Tue, 06 Oct 2026 13:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-119 CWE-122

Tue, 06 Oct 2026 09:00:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: ALSA: 6fire: fix OOB write from device-reported iso length usb6fire_pcm_in_urb_handler() sizes each outgoing isochronous packet as (actual_length - 4) / (in_n_analog << 2) * (out_n_analog << 2) + 4, where actual_length is the unsigned length the device reported for the matching IN packet. A packet completed with status 0 and actual_length < 4 wraps the subtraction to 0x7fffffec; a zero-length isochronous packet is legal on the bus, and the preceding loop rejects only non-zero status. The sum reaches memset() on out_urb->buffer, a 4832-byte object from kcalloc(PCM_MAX_PACKET_SIZE, PCM_N_PACKETS_PER_URB). Even without the wrap the result is out of bounds: at 88.2/96 kHz the 4-in/6-out scaling turns a full 420-byte IN packet into 628, so eight packets span 5024 bytes of that buffer. usb_submit_urb() rejects an over-long descriptor only after the memset() and the usb6fire_pcm_playback() copy of user PCM data have run. Guard the subtraction as the sibling usb6fire_pcm_capture() already does, and limit the frame count to what fits in rt->out_packet_size, the OUT endpoint's wMaxPacketSize. This bounds total_length by the buffer size while keeping each packet length aligned to a whole output frame. BUG: KASAN: out-of-bounds in usb6fire_pcm_in_urb_handler (sound/usb/6fire/pcm.c:338) Write of size 18446744073709551456 at addr ffff88802a3d0000 by task vhci_rx/5018 Call Trace: dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:595) kasan_check_range (mm/kasan/generic.c:186 mm/kasan/generic.c:200) __asan_memset (mm/kasan/shadow.c:84) usb6fire_pcm_in_urb_handler (sound/usb/6fire/pcm.c:338) __usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1657) usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1741) vhci_rx_loop (drivers/usb/usbip/vhci_rx.c:107 drivers/usb/usbip/vhci_rx.c:242) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) Allocated by task 10: __kmalloc_cache_noprof (mm/slub.c:5563) usb6fire_pcm_init (sound/usb/6fire/pcm.c:560 sound/usb/6fire/pcm.c:595) usb6fire_chip_probe (sound/usb/6fire/chip.c:133) usb_probe_interface (drivers/usb/core/driver.c:399) The buggy address belongs to the object at ffff88802a3d0000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 0 bytes inside of 4832-byte region [ffff88802a3d0000, ffff88802a3d12e0) Kernel panic - not syncing: Fatal exception in interrupt
Title		ALSA: 6fire: fix OOB write from device-reported iso length
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/001ba7c1d9677225a5ecbc3e60d4865c08bb21d8 https://git.kernel.org/stable/c/1589afe2d099d3e817873bc474676968d7080410 https://git.kernel.org/stable/c/246de677552fe5dede293a1543b632e9853f31e4 https://git.kernel.org/stable/c/61e665fb48e9eee44ec6d610514af383b1802cc1 https://git.kernel.org/stable/c/cdc31537012bc7a58c95c6750db321b69dd802bb https://git.kernel.org/stable/c/ea11ade10583cc45af515d6b24510dbfa0184ca6

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-10-06T08:46:08.388Z

Updated: 2026-10-19T09:17:22.807Z

Reserved: 2026-09-25T10:25:14.339Z

Link: CVE-2026-98312

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-10-06T09:18:22.727

Modified: 2026-10-19T10:18:33.290

Link: CVE-2026-98312

Redhat

Severity : Moderate

Publid Date: 2026-10-06T00:00:00Z

Links: CVE-2026-98312 - Bugzilla

OpenCVE Enrichment

Updated: 2026-10-10T02:00:11Z

Weaknesses

CWE-787
Out-of-bounds Write

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Subscriptions

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