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CVE Record

CVE-2022-50375: tty: serial: fsl_lpuart: disable dma rx/tx use flags in lpuart_dma_shutdown

In the Linux kernel, the following vulnerability has been resolved: tty: serial: fsl_lpuart: disable dma rx/tx use flags in lpuart_dma_shutdown lpuart_dma_shutdown tears down lpuart dma, but lpuart_flush_buffer can still occur which in turn tries to access dma apis if lpuart_dma_tx_use flag is true. At this point since dma is torn down, these dma apis can abort. Set lpuart_dma_tx_use and the corresponding rx flag lpuart_dma_rx_use to false in lpuart_dma_shutdown so that dmas are not accessed after they are relinquished. Otherwise, when try to kill btattach, kernel may panic. This patch may fix this issue. root@imx8ulpevk:~# btattach -B /dev/ttyLP2 -S 115200 ^C[ 90.182296] Internal error: synchronous external abort: 96000210 [#1] PREEMPT SMP [ 90.189806] Modules linked in: moal(O) mlan(O) [ 90.194258] CPU: 0 PID: 503 Comm: btattach Tainted: G O 5.15.32-06136-g34eecdf2f9e4 #37 [ 90.203554] Hardware name: NXP i.MX8ULP 9X9 EVK (DT) [ 90.208513] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 90.215470] pc : fsl_edma3_disable_request+0x8/0x60 [ 90.220358] lr : fsl_edma3_terminate_all+0x34/0x20c [ 90.225237] sp : ffff800013f0bac0 [ 90.228548] x29: ffff800013f0bac0 x28: 0000000000000001 x27: ffff000008404800 [ 90.235681] x26: ffff000008404960 x25: ffff000008404a08 x24: ffff000008404a00 [ 90.242813] x23: ffff000008404a60 x22: 0000000000000002 x21: 0000000000000000 [ 90.249946] x20: ffff800013f0baf8 x19: ffff00000559c800 x18: 0000000000000000 [ 90.257078] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 90.264211] x14: 0000000000000003 x13: 0000000000000000 x12: 0000000000000040 [ 90.271344] x11: ffff00000600c248 x10: ffff800013f0bb10 x9 : ffff000057bcb090 [ 90.278477] x8 : fffffc0000241a08 x7 : ffff00000534ee00 x6 : ffff000008404804 [ 90.285609] x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff0000055b3480 [ 90.292742] x2 : ffff8000135c0000 x1 : ffff00000534ee00 x0 : ffff00000559c800 [ 90.299876] Call trace: [ 90.302321] fsl_edma3_disable_request+0x8/0x60 [ 90.306851] lpuart_flush_buffer+0x40/0x160 [ 90.311037] uart_flush_buffer+0x88/0x120 [ 90.315050] tty_driver_flush_buffer+0x20/0x30 [ 90.319496] hci_uart_flush+0x44/0x90 [ 90.323162] +0x34/0x12c [ 90.327253] tty_ldisc_close+0x38/0x70 [ 90.331005] tty_ldisc_release+0xa8/0x190 [ 90.335018] tty_release_struct+0x24/0x8c [ 90.339022] tty_release+0x3ec/0x4c0 [ 90.342593] __fput+0x70/0x234 [ 90.345652] ____fput+0x14/0x20 [ 90.348790] task_work_run+0x84/0x17c [ 90.352455] do_exit+0x310/0x96c [ 90.355688] do_group_exit+0x3c/0xa0 [ 90.359259] __arm64_sys_exit_group+0x1c/0x20 [ 90.363609] invoke_syscall+0x48/0x114 [ 90.367362] el0_svc_common.constprop.0+0xd4/0xfc [ 90.372068] do_el0_svc+0x2c/0x94 [ 90.375379] el0_svc+0x28/0x80 [ 90.378438] el0t_64_sync_handler+0xa8/0x130 [ 90.382711] el0t_64_sync+0x1a0/0x1a4 [ 90.386376] Code: 17ffffda d503201f d503233f f9409802 (b9400041) [ 90.392467] ---[ end trace 2f60524b4a43f1f6 ]--- [ 90.397073] note: btattach[503] exited with preempt_count 1 [ 90.402636] Fixing recursive fault but reboot is needed!

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can crash affected systems when the Freescale/NXP LPUART serial driver tears down DMA but later code still uses DMA state. The documented impact is availability: a local user path can trigger a kernel panic, requiring reboot.

Executive priority

Treat as a moderate availability risk for affected embedded Linux products. It is not described as remote code execution, but a kernel panic can disrupt operational technology, appliances, or field devices that depend on serial peripherals.

Technical view

The fsl_lpuart driver’s DMA shutdown path failed to clear transmit and receive DMA-use flags. A later lpuart_flush_buffer path could call DMA APIs after DMA resources were relinquished, producing a synchronous external abort and kernel panic. CVSS is 5.5: local, low privileges, no confidentiality or integrity impact, high availability impact.

Likely exposure

Exposure is most likely on embedded Linux systems using the fsl_lpuart serial driver with DMA, including NXP i.MX-class environments shown in the report. Standard systems without this hardware or driver path are less likely exposed.

Exploitation context

The provided bundle does not show CISA KEV listing or public active exploitation. The demonstrated failure involves locally interacting with a serial-attached Bluetooth workflow and terminating it, causing a panic on affected hardware.

Researcher notes

Evidence is limited to the CVE record and kernel stable references. The root cause and fix are clear, but exploit prevalence, affected downstream vendors, and exact backport coverage require vendor-specific verification.

Mitigation direction

  • Apply a vendor or kernel stable update containing the referenced fsl_lpuart DMA shutdown fix.
  • Prioritize devices using fsl_lpuart serial ports with DMA enabled.
  • Check Linux distribution or device-vendor advisories for backported fixed kernel builds.
  • Plan reboot windows for embedded devices where kernel replacement is required.

Validation and detection

  • Inventory kernels and identify devices using the fsl_lpuart driver.
  • Check whether the referenced stable fix is present in the deployed kernel tree.
  • Review crash logs for lpuart_flush_buffer, fsl_edma3, or synchronous external abort traces.
  • Confirm vendor firmware or kernel release notes include this CVE or equivalent patch.
Prepared
Confidence
high
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

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CVE-2022-50375 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
7Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2022-50375Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux6250cc30c4c4e25393ba247f71bdc04b6af3191b, 6250cc30c4c4e25393ba247f71bdc04b6af3191b, 6250cc30c4c4e25393ba247f71bdc04b6af3191b, 6250cc30c4c4e25393ba247f71bdc04b6af3191b, 6250cc30c4c4e25393ba247f71bdc04b6af3191b, 6250cc30c4c4e25393ba247f71bdc04b6af3191bunaffected
LinuxLinux4.9, 0, 5.4.220, 5.10.150, 5.15.75, 5.19.17, 6.0.3, 6.1affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.