# CVE-2026-98761: usb: typec: tcpm: recover after failure to start the frs ams

> A physical USB cable disconnection during a fast role swap can leave VBUS powered, causing a denial of service in the Linux kernel USB Type-C subsystem.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-108984, BELL-CVE-2026-98761, DEBIAN-CVE-2026-98761, GHSA-fcv9-h4wq-59j8, UBUNTU-CVE-2026-98761

## What is CVE-2026-98761?

CVE-2026-98761 is a denial of service vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

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

usb: typec: tcpm: recover after failure to start the frs ams

Reset the port if the tcpm fails to start the FAST_ROLE_SWAP AMS by
initiating error recovery on it.

This helps in cases where some cables (incorrectly) signal an FRS to
an FRS capable port during disconnection. The TCPC autonomously starts
sourcing VBUS on detecting the FRS signal. However, the VBUS sourcing is
left on when the FAST_ROLE_SWAP AMS fails to start (as tcpm_sink_tx_ok
is 0 as CC is open due to the cable disconnect). This is because the
code sets the state to INVALID_STATE without resetting the port state.

Log snippet before changes:
[  101.401960] AMS FAST_ROLE_SWAP start
[  101.401971] Sink TX No Go
[  101.401982] sourcing vbus
[  101.401987] VBUS on
[  101.402159] VBUS on
[  109.257809] CC1: 0 -> 0, CC2: 5 -> 0 [state SNK_READY, polarity 1, disconnected]
[  111.267442] VBUS on

After changes:
[   70.541211] AMS FAST_ROLE_SWAP start
[   70.541220] Sink TX No Go
[   70.541228] state change SNK_READY -> ERROR_RECOVERY [rev3 NONE_AMS]
[   70.541362] VBUS on
[   70.541365] sourcing vbus
[   70.541367] VBUS on
[   70.541374] state change ERROR_RECOVERY -> PORT_RESET [rev3 NONE_AMS]
[   70.541410] disable vbus discharge ret:0
[   70.543028] Setting usb_comm capable false
[   70.544009] Setting voltage/current limit 0 mV 0 mA
[   70.544034] polarity 0
[   70.544239] Requesting mux state 0, usb-role 0, orientation 0
[   70.555550] cc:=0
[   70.555595] pending state change PORT_RESET -> PORT_RESET_WAIT_OFF @ 100 ms [rev3 NONE_AMS]
[   70.555697] VBUS off
[   70.555702] VBUS VSAFE0V
[   70.555762] CC1: 5 -> 0, CC2: 0 -> 0 [state PORT_RESET, polarity 0, disconnected]
[   70.587794] VBUS off
[   70.587799] VBUS VSAFE0V
[   70.655672] state change PORT_RESET -> PORT_RESET_WAIT_OFF [delayed 100 ms]
[   70.655682] state change PORT_RESET_WAIT_OFF -> SNK_UNATTACHED [rev3 NONE_AMS]
[   70.655686] Start toggling
[   70.656274] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]

## Which versions are affected by CVE-2026-98761?


## How do I fix CVE-2026-98761?

Apply the vendor's patch.

## Is CVE-2026-98761 being exploited?

There is no known exploitation of CVE-2026-98761 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98761 and fix it if it is affected.

What it is: CVE-2026-98761 is a denial of service vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-98761 in the wild and no public exploit code.

Affected product: Linux. 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-2026-98761/ (Markdown: https://insights.sbomify.com/CVE-2026-98761/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98761
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98761
- OSV: https://osv.dev/vulnerability/CVE-2026-98761

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98761/
Summaries are generated and may contain mistakes; the official description above is the record.