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Response snapshot Oct 30, 2026, 17:36 UTC

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VulnerabilityCVE-2026-80989

Linux kernel: net: thunderbolt: Mark the connection down when bringing it up fails

In the Linux kernel, the following vulnerability has been resolved: net: thunderbolt: Mark the connection down when bringing it up fails Every failure path in tbnet_connected_work() undoes its own work and returns without clearing login_sent, so the connection still looks established.

At a glance

Exploited
Not known
Severity
8.8 High (CVSS 3.1)
Chance of exploitation
0.3% in the next 30 days
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-80989 (opens a new tab)

What happened

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

net: thunderbolt: Mark the connection down when bringing it up fails

Every failure path in tbnet_connected_work() undoes its own work and returns without clearing login_sent, so the connection still looks established.

The next tbnet_tear_down() therefore takes its main branch and repeats a teardown that already happened: it stops rings that are already stopped, which is a dev_WARN() and fatal under panic_on_warn, and it releases net->remote_transmit_path even on the HopID mismatch path, where this connection never owned that id, silently freeing one that someone else is still using.

Continue reading

Clear login_sent on those paths. That is enough for tbnet_tear_down() to leave the unwound state alone, and login_received has to stay set: it records that the peer has logged in and carries the transmit path it gave us, which nothing on this side can make the peer send again.

Two things change beyond keeping the teardown out of the way: the logout request in that block is no longer sent, and the peer's next login request now re-queues our login work rather than connected_work, giving the connection a fresh login instead of a retry on stale state.

Scores and how they were measured

CVSS base severity

8.8

Version 3.1As of

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

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.3%

Scored Percentile 27.8%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-80989 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  5. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-80989, scored 2026-10-30. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 30). Linux kernel: net: thunderbolt: Mark the connection down when bringing it up fails (CVE-2026-80989). https://kevwire.com/record/CVE-2026-80989

MLA

"Linux kernel: net: thunderbolt: Mark the connection down when bringing it up fails (CVE-2026-80989)." KEVWire, 30 Oct. 2026, kevwire.com/record/CVE-2026-80989.

Chicago

KEVWire. "Linux kernel: net: thunderbolt: Mark the connection down when bringing it up fails (CVE-2026-80989)." Last modified October 30, 2026. https://kevwire.com/record/CVE-2026-80989.

Evidence summary (plain text)

Linux kernel: net: thunderbolt: Mark the connection down when bringing it up fails (Sep 11, 2026).
In the Linux kernel, the following vulnerability has been resolved:

net: thunderbolt: Mark the connection down when bringing it up fails

Every failure path in tbnet_connected_work() undoes its own work and
returns without clearing login_sent, so the connection still looks
established.
CVSS 8.8 (version 3.1; evidence as of Oct 30, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-80989).
EPSS 0.3% for the following 30 days, scored Oct 30, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-80989&date=2026-10-30).
Sources:
NVD CVE-2026-80989: https://nvd.nist.gov/vuln/detail/CVE-2026-80989
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T13:06:45.042Z&lastModEndDate=2026-10-30T14:50:57.069Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T12:22:16.957Z&lastModEndDate=2026-10-30T14:05:57.373Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T11:45:59.009Z&lastModEndDate=2026-10-30T13:20:57.281Z&resultsPerPage=500&startIndex=500
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-80989&date=2026-10-30
Record ID: CVE-2026-80989.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 30, 2026, 14:52 UTC. Ingestion is not an independent editorial investigation.

NVD status: Received. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail