CVE-2026-90379 - Vulnerability Details

- wifi: mt76: mt7921: Add PCIe AER handler support to prevent system crash

Description

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

wifi: mt76: mt7921: Add PCIe AER handler support to prevent system crash

When an AER error occurs and the bus is hung, the register reads return
0xFFFFFFFF, causing the DMA queue state to be corrupted and resulting in
an invalid memory access when accessing q->desc[] or q->entry[].

Unable to handle kernel paging request at virtual address
ffffffc01099eac0
pc : mt76_dma_add_buf+0x124/0x188 [mt76]
lr : mt76_dma_rx_fill+0x11c/0x1d8 [mt76]
sp : ffffffc016d9bbf0
x29: ffffffc016d9bc10 x28: 0000000000000000
x27: 0000000000000000 x26: ffffffb7855e50b8
x25: ffffffb80d04f000 x24: 0000000000000000
x23: 0000000000000ec0 x22: ffffffb796803648
x21: ffffffb796801f80 x20: ffffffb7968035f8
x19: 0000000000000ec0 x18: 0000000000000000
x17: 000000004ec00000 x16: 000000000ec00000
x15: ffffffc01099eac0 x14: 000000004ec00000
x13: 00000000ffc5a000 x12: ffffffc016d9bc32
x11: 00000000ffffffff x10: 0000000000000002
x9 : 0000000000000000 x8 : 000000000000b4ac
x7 : 0000000000000a20 x6 : ffffffb6c1806400
x5 : 0000000000000000 x4 : ffffffb80d04f000
x3 : 0000000000000000 x2 : 0000000000000001
x1 : 000000000ec04000 x0 : ffffffb7968035f8
Call trace:
mt76_dma_add_buf+0x124/0x188 [mt76 (HASH:1029 4)]
mt76_dma_rx_reset+0xe8/0xfc [mt76 (HASH:1029 4)]
mt7921_wpdma_reset+0x188/0x1b0 [mt7921e (HASH:ee48 5)]
mt7921e_mac_reset+0x128/0x418 [mt7921e (HASH:ee48 5)]
mt7921_mac_reset_work+0xac/0x1a8 [mt7921_common (HASH:f721 6)]
process_one_work+0x188/0x514
worker_thread+0x12c/0x300
kthread+0x140/0x1fc
ret_from_fork+0x10/0x30

Fix the invalid memory access by validating the DMA index read from the
hardware before it is used as a queue index. An out-of-range value, such
as the 0xFFFFFFFF returned while the bus is hung, is now clamped so it can
no longer corrupt q->head or q->tail. In addition, check the bus_hung flag
in mt7921_mac_reset_work() before attempting the reset sequence, reject MCU
messages while the bus is hung, and install no-op bus operations when an
unrecoverable AER error is detected, preventing further invalid hardware
accesses.

Due to hardware limitations - such as the lack of a connected hardware
reset pin or the absence of host re-probe functionality - affected Wi-Fi
devices may not fully recover to a normal operational state after
certain errors, even with AER enabled.

Published: 2026-09-17

Score: 8.8 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

The Linux mt7921 Wi‑Fi driver fails to validate a DMA index read from hardware when an Advanced Error Reporting event occurs and the PCIe bus is hung. It can receive a value of 0xFFFFFFFF and use it as a queue index, corrupting the DMA queue state and causing an out‑of‑bounds memory access to q->desc[] or q->entry[]. The invalid access triggers a kernel panic and a system crash, exposing the system to loss of availability and potential influence over integrity. This weakness falls under CWE‑787 and CWE‑20.

Affected Systems

The vulnerability affects any Linux system that includes the mt7921 driver for MT7921 Wi‑Fi hardware. Since the mt76/mt7921 driver is part of the default kernel tree, it is present in most mainstream Linux distributions that ship with that driver. The issue applies to all kernel releases prior to the commit that added PCIe AER handling in the driver.

Risk and Exploitability

The CVSS score of 8.8 categorizes the issue as high severity, while the EPSS score of less than 1% indicates that exploitation is currently unlikely and no widespread attacks have been reported. The vulnerability is not listed in the CISA KEV catalog. The likely attack vector is a PCIe AER event triggered by malformed Wi‑Fi traffic or firmware manipulation, which then causes the kernel to crash.

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
`17f1de56df051229988aab37e01971c9713c4a31`	affected	< 670b3dc4e3713542a9f002d38fb9d1740b9e342b
`17f1de56df051229988aab37e01971c9713c4a31`	affected	< f544bcba4721e1074e9bc6666f0ef4f8b96ddba8
`17f1de56df051229988aab37e01971c9713c4a31`	affected	< 915672c5ae32deeb72f4572856d123f314791136

Linux

affected

Version	Status	Constraints
`4.16`	affected	—
`0`	unaffected	< 4.16
`6.18.52`	unaffected	≤ 6.18.*
`7.2.6`	unaffected	≤ 7.2.*
`7.3-rc1`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[17f1de56df051229988aab37e01971c9713c4a31,670b3dc4e3713542a9f002d38fb9d1740b9e342b)`	affected	code_commit	—
`[17f1de56df051229988aab37e01971c9713c4a31,f544bcba4721e1074e9bc6666f0ef4f8b96ddba8)`	affected	code_commit	—
`[17f1de56df051229988aab37e01971c9713c4a31,915672c5ae32deeb72f4572856d123f314791136)`	affected	code_commit	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`4.16`	affected	generic	—
`[0,4.16)`	unaffected	generic	—
`[6.18.52,6.18.*]`	unaffected	generic	—
`[7.2.6,7.2.*]`	unaffected	generic	—
`[7.3-rc1,*]`	unaffected	generic	—

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Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the latest Linux kernel patch that adds PCIe AER handler support for the mt7921 driver (commit 670b3dc4e3713542a9f002d38fb9d1740b9e342b).
If an immediate kernel upgrade cannot be performed, consider disabling the mt7921 Wi‑Fi device in the BIOS/UEFI or unloading the mt76/mt7921 driver until the fix is applied.
Monitor kernel logs for AER or bus‑hung messages; if such errors occur frequently, replace the Wi‑Fi hardware or coordinate with hardware vendors for firmware updates.

Generated by OpenCVE AI on September 20, 2026 at 02:59 UTC.

Tracking

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Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

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 0.00375.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/670b3dc4e3713542a9f002d38fb9d1740b9e342b
https://git.kernel.org/stable/c/915672c5ae32deeb72f4572856d123f314791136
https://git.kernel.org/stable/c/f544bcba4721e1074e9bc6666f0ef4f8b96ddba8

History

Sun, 20 Sep 2026 03:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-20 CWE-787

Sun, 20 Sep 2026 01:45:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-125 CWE-129 CWE-787

Sat, 19 Sep 2026 14:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-125 CWE-129 CWE-787

Fri, 18 Sep 2026 21:30:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 8.8, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}`

Thu, 17 Sep 2026 16:30:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7921: Add PCIe AER handler support to prevent system crash When an AER error occurs and the bus is hung, the register reads return 0xFFFFFFFF, causing the DMA queue state to be corrupted and resulting in an invalid memory access when accessing q->desc[] or q->entry[]. Unable to handle kernel paging request at virtual address ffffffc01099eac0 pc : mt76_dma_add_buf+0x124/0x188 [mt76] lr : mt76_dma_rx_fill+0x11c/0x1d8 [mt76] sp : ffffffc016d9bbf0 x29: ffffffc016d9bc10 x28: 0000000000000000 x27: 0000000000000000 x26: ffffffb7855e50b8 x25: ffffffb80d04f000 x24: 0000000000000000 x23: 0000000000000ec0 x22: ffffffb796803648 x21: ffffffb796801f80 x20: ffffffb7968035f8 x19: 0000000000000ec0 x18: 0000000000000000 x17: 000000004ec00000 x16: 000000000ec00000 x15: ffffffc01099eac0 x14: 000000004ec00000 x13: 00000000ffc5a000 x12: ffffffc016d9bc32 x11: 00000000ffffffff x10: 0000000000000002 x9 : 0000000000000000 x8 : 000000000000b4ac x7 : 0000000000000a20 x6 : ffffffb6c1806400 x5 : 0000000000000000 x4 : ffffffb80d04f000 x3 : 0000000000000000 x2 : 0000000000000001 x1 : 000000000ec04000 x0 : ffffffb7968035f8 Call trace: mt76_dma_add_buf+0x124/0x188 [mt76 (HASH:1029 4)] mt76_dma_rx_reset+0xe8/0xfc [mt76 (HASH:1029 4)] mt7921_wpdma_reset+0x188/0x1b0 [mt7921e (HASH:ee48 5)] mt7921e_mac_reset+0x128/0x418 [mt7921e (HASH:ee48 5)] mt7921_mac_reset_work+0xac/0x1a8 [mt7921_common (HASH:f721 6)] process_one_work+0x188/0x514 worker_thread+0x12c/0x300 kthread+0x140/0x1fc ret_from_fork+0x10/0x30 Fix the invalid memory access by validating the DMA index read from the hardware before it is used as a queue index. An out-of-range value, such as the 0xFFFFFFFF returned while the bus is hung, is now clamped so it can no longer corrupt q->head or q->tail. In addition, check the bus_hung flag in mt7921_mac_reset_work() before attempting the reset sequence, reject MCU messages while the bus is hung, and install no-op bus operations when an unrecoverable AER error is detected, preventing further invalid hardware accesses. Due to hardware limitations - such as the lack of a connected hardware reset pin or the absence of host re-probe functionality - affected Wi-Fi devices may not fully recover to a normal operational state after certain errors, even with AER enabled.
Title		wifi: mt76: mt7921: Add PCIe AER handler support to prevent system crash
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/670b3dc4e3713542a9f002d38fb9d1740b9e342b https://git.kernel.org/stable/c/915672c5ae32deeb72f4572856d123f314791136 https://git.kernel.org/stable/c/f544bcba4721e1074e9bc6666f0ef4f8b96ddba8

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-09-17T16:09:17.297Z

Updated: 2026-09-18T17:54:55.903Z

Reserved: 2026-09-11T19:38:34.809Z

Link: CVE-2026-90379

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-09-17T17:17:37.170

Modified: 2026-09-18T18:17:55.917

Link: CVE-2026-90379

Redhat

No data.

OpenCVE Enrichment

Updated: 2026-09-20T03:00:11Z

Weaknesses

CWE-20
Improper Input Validation
CWE-787
Out-of-bounds Write

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Subscriptions

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