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Linux KernelOperating system · Linux

CVE-2026-53086

CRITICAL · 9.8 CVSS v3.1 Published 2026-06-24
Fix available
A fix is available. Upgrade to 6.1.175 / 6.6.141 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: net: bcmgenet: fix racing timeout handler The bcmgenet_timeout handler tries to take down all tx queues when a single queue times out. This is over zealous and causes many race conditions with queues that are still chugging along. Instead lets only restart the timed out queue.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A race condition exists in the Linux kernel's bcmgenet network driver where the timeout handler incorrectly takes down ALL transmit queues when only a single queue experiences a timeout. This overly aggressive behavior creates race conditions with queues that remain operational. The fix modifies the handler to only restart the specific queue that timed out, eliminating the unnecessary disruption to healthy queues.

MitigationUpdate the Linux kernel to the version containing the fix for CVE-2026-53086, or apply the vendor-supplied patch to the bcmgenet driver to ensure only the timed-out queue is restarted rather than all tx queues.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 4.2, < 6.1.175>= 6.2, < 6.6.141>= 6.7, < 6.12.91>= 6.13, < 6.18.33>= 6.19, < 7.0.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify bcmgenet driver is loaded
    Run 'lsmod | grep bcmgenet' or check 'lspci -k' for the network controller to confirm the Broadcom GENET driver is in use
    Affected if The bcmgenet driver is not loaded or not present - the system is not affected
  2. Check kernel version against vulnerable range
    Run 'uname -r' to get the kernel version and compare it to the known vulnerable version range for this CVE
    Affected if The installed kernel version falls within the vulnerable range before the patch was applied
  3. Confirm multiple transmit queues are configured
    Check driver parameters with 'ethtool -l <interface>' or review boot config for CONFIG_BCMGENET_MULTI_Q=1 or similar multi-queue settings
    Affected if Only a single TX queue is configured - the specific race condition bug cannot trigger; multiple queues must be enabled for the vulnerability to apply
  4. Inspect the timeout handler implementation
    Review the driver's source code in /drivers/net/ethernet/broadcom/genet/bcmgenet.c for the tx_timeout handler function, specifically looking for code that iterates over all queues rather than just the timed-out queue
    Affected if The timeout handler code shows it acts on all transmit queues instead of just the specific queue that experienced the timeout
  5. Check system logs for TX timeout events
    Review 'dmesg' or 'journalctl' for messages containing 'bcmgenet' and 'tx timeout' or 'TX timeout' warnings
    Affected if TX timeout messages appear in logs, indicating the problematic code path has been exercised

A system is affected if it runs a vulnerable kernel version with the bcmgenet driver loaded and has multiple transmit queues enabled, allowing the overzealous queue restart logic to create race conditions with functional queues.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 6.1.175 / 6.6.141 / 6.12.91 or later
Fixed in 6.1.1756.6.1416.12.91
Interim mitigation

Update the Linux kernel to the version containing the fix for CVE-2026-53086, or apply the vendor-supplied patch to the bcmgenet driver to ensure only the timed-out queue is restarted rather than all tx queues.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-53086 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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