CVE-2025-37940

Local denial of service via unyielding ftrace loop

Published May 20, 2025 · Updated May 11, 2026

Denial of service in affected Linux kernel branches from 4.11 allows local users to trigger a soft lockup via the ftrace graph filter. The ftrace_graph_set_hash() loop in kernel/trace/ftrace.c scans every traceable function without a scheduling point when processing set_graph_function input. Local access with permission to write the tracefs function-graph controls and a large traceable-function set are required; the watchdog event interrupts system responsiveness.

CVSS severity5.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in affected Linux kernel branches from 4.11 allows local users to trigger a soft lockup via the ftrace graph filter. The ftrace_graph_set_hash() loop in kernel/trace/ftrace.c scans every traceable function without a scheduling point when processing set_graph_function input. Local access with permission to write the tracefs function-graph controls and a large traceable-function set are required; the watchdog event interrupts system responsiveness.

The record

CVE
CVE-2025-37940
Published
May 20, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-667, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 20, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=4.11
  2. Affected versionversion=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <1fce9574b9d515bcb8a75379a8053e18602424e3
  3. Affected versionversion=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <42ea22e754ba4f2b86f8760ca27f6f71da2d982c
  4. Affected versionversion=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <4429535acab750d963fdc3dfcc9e0eee42f4d599
  5. Affected versionversion=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <5d336ac215e5c76e43ef4bca9ba699835e53e2fd
  6. Affected versionversion=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <618655d54c5f8af5d57b77491d08c0f0ff77d114
  7. Affected versionversion=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <72be43ff061a889c6ee648a330a42486cafa15a6
  8. Affected versionversion=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <8dd7d7280357596ba63dfdb4c1725d9dd24bd42a
  9. Affected versionversion=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <dd38803c9088b848c6b56f4f6d7efc4497bfde61
  10. Affected versionversion=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <e5b4ae6f01d4a510d5725eca7254519a1093920d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.11; version=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <1fce9574b9d515bcb8a75379a8053e18602424e3; version=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <42ea22e754ba4f2b86f8760ca27f6f71da2d982c; version=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <4429535acab750d963fdc3dfcc9e0eee42f4d599; version=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <5d336ac215e5c76e43ef4bca9ba699835e53e2fd; version=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <618655d54c5f8af5d57b77491d08c0f0ff77d114; version=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <72be43ff061a889c6ee648a330a42486cafa15a6; version=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <8dd7d7280357596ba63dfdb4c1725d9dd24bd42a; version=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <dd38803c9088b848c6b56f4f6d7efc4497bfde61; version=b9b0c831bed2682c2e3e9f5420fb6985549ef020 <e5b4ae6f01d4a510d5725eca7254519a1093920d

Published CVSS scores

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

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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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-667Improper Locking
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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