CVE-2025-39744

Local system hang via recursive IRQ exit

Published Sep 11, 2025 · Updated May 11, 2026

Kernel RCU deadlock in affected Linux releases allows local users to hang the system by running BPF code on the trace_tick_stop tracepoint. During irq_exit(), rcu_read_unlock_special() queues defer_qs_iw to the current CPU, whose IPI re-enters irq_exit() and recursively locks up. Local access and permission to load the tracepoint BPF program are required; the demonstrated consequence is a system hang.

CVSS severity7.1
High
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Kernel RCU deadlock in affected Linux releases allows local users to hang the system by running BPF code on the trace_tick_stop tracepoint. During irq_exit(), rcu_read_unlock_special() queues defer_qs_iw to the current CPU, whose IPI re-enters irq_exit() and recursively locks up. Local access and permission to load the tracepoint BPF program are required; the demonstrated consequence is a system hang.

The record

CVE
CVE-2025-39744
Published
Sep 11, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 11, 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=0864f057b050bc6dd68106b3185e02db5140012d <1cfa244f7198d325594e627574930b7b91df5bfe
  2. Affected versionversion=0864f057b050bc6dd68106b3185e02db5140012d <56c5ef194f4509df63fc0f7a91ea5973ce479b1e
  3. Affected versionversion=0864f057b050bc6dd68106b3185e02db5140012d <b41642c87716bbd09797b1e4ea7d904f06c39b7b
  4. Affected versionversion=0864f057b050bc6dd68106b3185e02db5140012d <ddebb2a7677673cf4438a04e1a48b8ed6b0c8e9a
  5. Affected versionversion=0864f057b050bc6dd68106b3185e02db5140012d <e7a375453cca2b8a0d2fa1b82b913f3fed7c0507
  6. Affected versionversion=5.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0864f057b050bc6dd68106b3185e02db5140012d <1cfa244f7198d325594e627574930b7b91df5bfe; version=0864f057b050bc6dd68106b3185e02db5140012d <56c5ef194f4509df63fc0f7a91ea5973ce479b1e; version=0864f057b050bc6dd68106b3185e02db5140012d <b41642c87716bbd09797b1e4ea7d904f06c39b7b; version=0864f057b050bc6dd68106b3185e02db5140012d <ddebb2a7677673cf4438a04e1a48b8ed6b0c8e9a; version=0864f057b050bc6dd68106b3185e02db5140012d <e7a375453cca2b8a0d2fa1b82b913f3fed7c0507; version=5.3

Published CVSS scores

5.5Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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

CWE-125Out-of-bounds Read
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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