CVE-2025-39813

Kernel crash via ftrace buffer-consumption race

Published Sep 16, 2025 · Updated Sep 16, 2025

Race condition in Linux kernel ftrace allows attackers to crash a panic-on-warning system by racing a trace dump with a trace_pipe read. In ftrace_dump_one(), another reader can empty the ring buffer after trace_empty() succeeds, leaving iter.seq reset and unpopulated before trace_printk_seq() checks equal zero lengths. The demonstrated path requires administrative access to /proc/sysrq-trigger and a concurrent trace_pipe reader; without panic_on_warn, it emits a one-time warning rather than crashing.

CVSS severity4.7
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux kernel ftrace allows attackers to crash a panic-on-warning system by racing a trace dump with a trace_pipe read. In ftrace_dump_one(), another reader can empty the ring buffer after trace_empty() succeeds, leaving iter.seq reset and unpopulated before trace_printk_seq() checks equal zero lengths. The demonstrated path requires administrative access to /proc/sysrq-trigger and a concurrent trace_pipe reader; without panic_on_warn, it emits a one-time warning rather than crashing.

The record

CVE
CVE-2025-39813
Published
Sep 16, 2025
Updated
Sep 16, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-362, T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2025Record 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=2.6.28
  2. Affected versionversion=d769041f865330034131525ee6a7f72eb4af2a24 <28c8fb7ae2ad27d81c8de3c4fe608c509f6a18aa
  3. Affected versionversion=d769041f865330034131525ee6a7f72eb4af2a24 <4013aef2ced9b756a410f50d12df9ebe6a883e4a
  4. Affected versionversion=d769041f865330034131525ee6a7f72eb4af2a24 <5ab0ec206deb99eb3baf8f1d7602aeaa91dbcc85
  5. Affected versionversion=d769041f865330034131525ee6a7f72eb4af2a24 <a6f0f8873cc30fd4543b09adf03f7f51d293f0e6
  6. Affected versionversion=d769041f865330034131525ee6a7f72eb4af2a24 <ced94e137e6cd5e79c65564841d3b7695d0f5fa3
  7. Affected versionversion=d769041f865330034131525ee6a7f72eb4af2a24 <e80ff23ba8bdb0f41a1afe2657078e4097d13a9a
  8. Affected versionversion=d769041f865330034131525ee6a7f72eb4af2a24 <f299353e7ccbcc5c2ed8993c48fbe7609cbe729a
  9. Affected versionversion=d769041f865330034131525ee6a7f72eb4af2a24 <fbd4cf7ee4db65ef36796769fe978e9eba6f0de4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.28; version=d769041f865330034131525ee6a7f72eb4af2a24 <28c8fb7ae2ad27d81c8de3c4fe608c509f6a18aa; version=d769041f865330034131525ee6a7f72eb4af2a24 <4013aef2ced9b756a410f50d12df9ebe6a883e4a; version=d769041f865330034131525ee6a7f72eb4af2a24 <5ab0ec206deb99eb3baf8f1d7602aeaa91dbcc85; version=d769041f865330034131525ee6a7f72eb4af2a24 <a6f0f8873cc30fd4543b09adf03f7f51d293f0e6; version=d769041f865330034131525ee6a7f72eb4af2a24 <ced94e137e6cd5e79c65564841d3b7695d0f5fa3; version=d769041f865330034131525ee6a7f72eb4af2a24 <e80ff23ba8bdb0f41a1afe2657078e4097d13a9a; version=d769041f865330034131525ee6a7f72eb4af2a24 <f299353e7ccbcc5c2ed8993c48fbe7609cbe729a; version=d769041f865330034131525ee6a7f72eb4af2a24 <fbd4cf7ee4db65ef36796769fe978e9eba6f0de4

Published CVSS scores

4.7NIST NVDCVSS:3.1/AV:L/AC:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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