CVE-2026-74321

System crash via retained error-pointer dereference

Published Aug 15, 2026 · Updated Aug 15, 2026

Invalid pointer dereference in affected Linux btrfs kernels allows attackers to crash the system during delayed-reference processing. __btrfs_run_delayed_refs() retains ERR_PTR(-EAGAIN) in locked_ref after btrfs_select_ref_head() fails, then passes that error pointer to spin_lock(). Reachability requires a workload that drives delayed references on a mounted btrfs filesystem; the bounded consequence is a kernel crash.

CVSS severity7.5
High
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Invalid pointer dereference in affected Linux btrfs kernels allows attackers to crash the system during delayed-reference processing. __btrfs_run_delayed_refs() retains ERR_PTR(-EAGAIN) in locked_ref after btrfs_select_ref_head() fails, then passes that error pointer to spin_lock(). Reachability requires a workload that drives delayed references on a mounted btrfs filesystem; the bounded consequence is a kernel crash.

The record

CVE
CVE-2026-74321
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <015dc4a1e0c2cba551d4620eba13d26d5081dc34
  2. Affected versionversion=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <3b15d02be05e74321adb1e0ae0cb4ccfba7c6cb1
  3. Affected versionversion=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <486f8298b6188ff11ef1f4be7f1d5d2e4d1b1fae
  4. Affected versionversion=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <65770111a2d47c2b15e20b2ba92bb12198f289d4
  5. Affected versionversion=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <9faa6b69ad73f03c7bde53e07d75a28822dc9a1a
  6. Affected versionversion=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <a71143590ce9764dbcb47617647592ff8b4d48bc
  7. Affected versionversion=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <ba9fa2ff5981589bb49094d3358c339b37c47f53
  8. Affected versionversion=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <c372ca227e16bace86f1df1fa4ae6849e2fcfa28
  9. Affected versionversion=4.20

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <015dc4a1e0c2cba551d4620eba13d26d5081dc34; version=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <3b15d02be05e74321adb1e0ae0cb4ccfba7c6cb1; version=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <486f8298b6188ff11ef1f4be7f1d5d2e4d1b1fae; version=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <65770111a2d47c2b15e20b2ba92bb12198f289d4; version=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <9faa6b69ad73f03c7bde53e07d75a28822dc9a1a; version=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <a71143590ce9764dbcb47617647592ff8b4d48bc; version=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <ba9fa2ff5981589bb49094d3358c339b37c47f53; version=0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <c372ca227e16bace86f1df1fa4ae6849e2fcfa28; version=4.20

Published CVSS scores

7.5UbuntuCVSS:3.1/AV:N/AC:L/PR:N/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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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