# CVE-2025-22022: usb: xhci: Apply the link chain quirk on NEC isoc endpoints

> A flaw in the Linux kernel xHCI driver for NEC USB controllers can cause IOMMU faults and memory corruption, potentially leading to system crashes or code execution.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Apr 2025
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-62762, AZL-68982, BELL-CVE-2025-22022, DEBIAN-CVE-2025-22022, GHSA-4j7f-c5p6-h9j2, ROOT-OS-DEBIAN-11-CVE-2025-22022, ROOT-OS-DEBIAN-12-CVE-2025-22022, ROOT-OS-UBUNTU-2204-CVE-2025-22022, ROOT-OS-UBUNTU-2404-CVE-2025-22022, UBUNTU-CVE-2025-22022

## What is CVE-2025-22022?

CVE-2025-22022 is a high-severity memory corruption vulnerability in Linux kernel, published on 16 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

usb: xhci: Apply the link chain quirk on NEC isoc endpoints

Two clearly different specimens of NEC uPD720200 (one with start/stop
bug, one without) were seen to cause IOMMU faults after some Missed
Service Errors. Faulting address is immediately after a transfer ring
segment and patched dynamic debug messages revealed that the MSE was
received when waiting for a TD near the end of that segment:

[ 1.041954] xhci_hcd: Miss service interval error for slot 1 ep 2 expected TD DMA ffa08fe0
[ 1.042120] xhci_hcd: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0005 address=0xffa09000 flags=0x0000]
[ 1.042146] xhci_hcd: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0005 address=0xffa09040 flags=0x0000]

It gets even funnier if the next page is a ring segment accessible to
the HC. Below, it reports MSE in segment at ff1e8000, plows through a
zero-filled page at ff1e9000 and starts reporting events for TRBs in
page at ff1ea000 every microframe, instead of jumping to seg ff1e6000.

[ 7.041671] xhci_hcd: Miss service interval error for slot 1 ep 2 expected TD DMA ff1e8fe0
[ 7.041999] xhci_hcd: Miss service interval error for slot 1 ep 2 expected TD DMA ff1e8fe0
[ 7.042011] xhci_hcd: WARN: buffer overrun event for slot 1 ep 2 on endpoint
[ 7.042028] xhci_hcd: All TDs skipped for slot 1 ep 2. Clear skip flag.
[ 7.042134] xhci_hcd: WARN: buffer overrun event for slot 1 ep 2 on endpoint
[ 7.042138] xhci_hcd: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2 comp_code 31
[ 7.042144] xhci_hcd: Looking for event-dma 00000000ff1ea040 trb-start 00000000ff1e6820 trb-end 00000000ff1e6820
[ 7.042259] xhci_hcd: WARN: buffer overrun event for slot 1 ep 2 on endpoint
[ 7.042262] xhci_hcd: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2 comp_code 31
[ 7.042266] xhci_hcd: Looking for event-dma 00000000ff1ea050 trb-start 00000000ff1e6820 trb-end 00000000ff1e6820

At some point completion events change from Isoch Buffer Overrun to
Short Packet and the HC finally finds cycle bit mismatch in ff1ec000.

[ 7.098130] xhci_hcd: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2 comp_code 13
[ 7.098132] xhci_hcd: Looking for event-dma 00000000ff1ecc50 trb-start 00000000ff1e6820 trb-end 00000000ff1e6820
[ 7.098254] xhci_hcd: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2 comp_code 13
[ 7.098256] xhci_hcd: Looking for event-dma 00000000ff1ecc60 trb-start 00000000ff1e6820 trb-end 00000000ff1e6820
[ 7.098379] xhci_hcd: Overrun event on slot 1 ep 2

It's possible that data from the isochronous device were written to
random buffers of pending TDs on other endpoints (either IN or OUT),
other devices or even other HCs in the same IOMMU domain.

Lastly, an error from a different USB device on another HC. Was it
caused by the above? I don't know, but it may have been. The disk
was working without any other issues and generated PCIe traffic to
starve the NEC of upstream BW and trigger those MSEs. The two HCs
shared one x1 slot by means of a commercial "PCIe splitter" board.

[ 7.162604] usb 10-2: reset SuperSpeed USB device number 3 using xhci_hcd
[ 7.178990] sd 9:0:0:0: [sdb] tag#0 UNKNOWN(0x2003) Result: hostbyte=0x07 driverbyte=DRIVER_OK cmd_age=0s
[ 7.179001] sd 9:0:0:0: [sdb] tag#0 CDB: opcode=0x28 28 00 04 02 ae 00 00 02 00 00
[ 7.179004] I/O error, dev sdb, sector 67284480 op 0x0:(READ) flags 0x80700 phys_seg 5 prio class 0

Fortunately, it appears that this ridiculous bug is avoided by setting
the chain bit of Link TRBs on isochronous rings. Other ancient HCs are
known which also expect the bit to be set and they ignore Link TRBs if
it's not. Reportedly, 0.95 spec guaranteed that the bit is set.

The bandwidth-starved NEC HC running a 32KB/uframe UVC endpoint reports
tens of MSEs per second and runs into the bug within seconds. Chaining
Link TRBs allows the same workload to run for many minutes, many times.

No ne
---truncated---

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2025-22022?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-22022?

Apply the vendor's patch.

## Is CVE-2025-22022 being exploited?

There is no known exploitation of CVE-2025-22022 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-22022 and fix it if it is affected.

What it is: CVE-2025-22022 is a high-severity memory corruption vulnerability in Linux kernel, published on 16 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-22022 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-22022/ (Markdown: https://insights.sbomify.com/CVE-2025-22022/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-22022
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-22022
- OSV: https://osv.dev/vulnerability/CVE-2025-22022

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-22022/
Summaries are generated and may contain mistakes; the official description above is the record.