CVE-2026-43308

Local kernel crash via unexpected delayed reference

Published May 8, 2026 · Updated May 8, 2026

Reachable assertion in Linux Kernel 2.6.31 through 6.19.5 allows local users to crash the system during btrfs delayed-reference processing. The run_one_delayed_ref() function calls BUG() for a node type outside its handled tree, data, and owner-reference cases instead of returning an error. Low-privileged local access and btrfs use are required; triggering the assertion stops the running kernel without disclosing or modifying data.

CVSS severity5.5
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in Linux Kernel 2.6.31 through 6.19.5 allows local users to crash the system during btrfs delayed-reference processing. The run_one_delayed_ref() function calls BUG() for a node type outside its handled tree, data, and owner-reference cases instead of returning an error. Low-privileged local access and btrfs use are required; triggering the assertion stops the running kernel without disclosing or modifying data.

The record

CVE
CVE-2026-43308
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5549743e11c06da23cfa7712a994b9f1e69064c6
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c7d1d4ff56744074e005771aff193b927392d51f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5549743e11c06da23cfa7712a994b9f1e69064c6; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c7d1d4ff56744074e005771aff193b927392d51f

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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