Skip to main content

Linux CVE-2025-39744

HIGH
Out-of-bounds Read (CWE-125)
2025-09-11 416baaa9-dc9f-4396-8d5f-8c081fb06d67
7.1
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, read limits
MITRE ATT&CK

1 technique across 1 tactic: Collection

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 7.1 (HIGH). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required. EPSS exploitation probability: 0.01%.

Exploit ScenarioDerived

A local attacker with access to the system could read data from memory outside the intended buffer boundaries.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.0% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Mar 28, 2026

In the Linux kernel, the following vulnerability has been resolved: rcu: Fix rcu_read_unlock() deadloop due to IRQ work During rcu_read_unlock_special(), if this happens during irq_exit(), we can. Rated high severity (CVSS 7.1), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Validate array indices and buffer lengths. Use memory-safe languages. Enable AddressSanitizer during testing.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Out-of-bounds Read (CWE-125), which allows attackers to read data from memory outside the intended buffer boundaries. In the Linux kernel, the following vulnerability has been resolved: rcu: Fix rcu_read_unlock() deadloop due to IRQ work During rcu_read_unlock_special(), if this happens during irq_exit(), we can lockup if an IPI is issued. This is because the IPI itself triggers the irq_exit() path causing a recursive lock up. This is precisely what Xiongfeng found when invoking a BPF program on the trace_tick_stop() tracepoint As shown in the trace below. Fix by managing the irq_work state correctly. irq_exit() __irq_exit_rcu() /* in_hardirq() returns false after this */ preempt_count_sub(HARDIRQ_OFFSET) tick_irq_exit() tick_nohz_irq_exit() tick_nohz_stop_sched_tick() trace_tick_stop() /* a bpf prog is hooked on this trace point */ __bpf_trace_tick_stop() bpf_trace_run2() rcu_read_unlock_special() /* will send a IPI to itself */ irq_work_queue_on(&rdp->defer_qs_iw, rdp->cpu); A simple reproducer can also be obtained by doing the following in tick_irq_exit(). It will hang on boot without the patch: static inline void tick_irq_exit(void) { + rcu_read_lock(); + WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, true); + rcu_read_unlock(); + [neeraj: Apply Frederic's suggested fix for PREEMPT_RT] Affected products include: Linux Linux Kernel.

Know when the next one hits your stack

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources

No credit card · 7-day full trial

Severity by source

NVD PRIMARY 7.1 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
SUSE HIGH

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

Lifecycle Timeline

2
Patch released
Mar 28, 2026 - 19:11 nvd
Patch available
CVE Published
Sep 11, 2025 - 17:15 nvd
HIGH 7.1

DescriptionNVD

In the Linux kernel, the following vulnerability has been resolved:

rcu: Fix rcu_read_unlock() deadloop due to IRQ work

During rcu_read_unlock_special(), if this happens during irq_exit(), we can lockup if an IPI is issued. This is because the IPI itself triggers the irq_exit() path causing a recursive lock up.

This is precisely what Xiongfeng found when invoking a BPF program on the trace_tick_stop() tracepoint As shown in the trace below. Fix by managing the irq_work state correctly.

irq_exit() __irq_exit_rcu() /* in_hardirq() returns false after this */ preempt_count_sub(HARDIRQ_OFFSET) tick_irq_exit() tick_nohz_irq_exit() tick_nohz_stop_sched_tick() trace_tick_stop() /* a bpf prog is hooked on this trace point */ __bpf_trace_tick_stop() bpf_trace_run2() rcu_read_unlock_special() /* will send a IPI to itself */ irq_work_queue_on(&rdp->defer_qs_iw, rdp->cpu);

A simple reproducer can also be obtained by doing the following in tick_irq_exit(). It will hang on boot without the patch:

static inline void tick_irq_exit(void) { + rcu_read_lock(); + WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, true); + rcu_read_unlock(); +

[neeraj: Apply Frederic's suggested fix for PREEMPT_RT]

Executive ViewAI

Why It Matters

CVE-2025-39744 presents moderate security risk, a out-of-bounds read vulnerability rated CVSS 7.1. Exploitation could compromise the security of affected deployments. A patch is available and should be applied as part of regular vulnerability management.

Business Impact: Moderate
Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score
0.0%
Top 97% exploitable
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No

Priority Score

36
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +36
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)NVD

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

Vendor StatusVendor

SUSE

Severity: High
Product Status
Container suse/sl-micro/6.0/base-os-container:2.1.3-7.57 Container suse/sl-micro/6.1/base-os-container:2.2.1-5.40 Image SL-Micro Image SL-Micro-Azure Image SL-Micro-BYOS-Azure Image SL-Micro-BYOS-EC2 Image SL-Micro-BYOS-GCE Image SL-Micro-EC2 Image SLE-Micro Image SLE-Micro-Azure Image SLE-Micro-BYOS Image SLE-Micro-BYOS-Azure Image SLE-Micro-BYOS-EC2 Image SLE-Micro-BYOS-GCE Image SLE-Micro-EC2 Image SLE-Micro-GCE Image SUSE-Multi-Linux-Manager-Proxy-BYOS-Azure Image SUSE-Multi-Linux-Manager-Proxy-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Proxy-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-Azure-llc Image SUSE-Multi-Linux-Manager-Server-Azure-ltd Image SUSE-Multi-Linux-Manager-Server-BYOS-Azure Image SUSE-Multi-Linux-Manager-Server-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Server-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-EC2-llc Image SUSE-Multi-Linux-Manager-Server-EC2-ltd Affected
Container suse/sl-micro/6.0/kvm-os-container:2.1.3-6.80 Container suse/sl-micro/6.1/kvm-os-container:2.2.1-5.41 Affected
Container suse/sl-micro/6.0/rt-os-container:2.1.3-7.95 Container suse/sl-micro/6.1/rt-os-container:2.2.1-5.34 Affected
Image SLES-Azure-3P Image SLES-Azure-Basic Image SLES-Azure-Standard Image SLES-BYOS-Azure Image SLES-BYOS-EC2 Image SLES-BYOS-GCE Image SLES-CHOST-BYOS-Aliyun Image SLES-CHOST-BYOS-Azure Image SLES-CHOST-BYOS-EC2 Image SLES-CHOST-BYOS-GCE Image SLES-CHOST-BYOS-GDC Image SLES-CHOST-BYOS-SAP-CCloud Image SLES-EC2 Image SLES-GCE Image SLES-Hardened-BYOS-Azure Image SLES-Hardened-BYOS-EC2 Image SLES-Hardened-BYOS-GCE Image SLES-SAPCAL-Azure Image SLES-SAPCAL-EC2 Image SLES-SAPCAL-GCE Affected
Image SLES-SAP-Azure Image SLES-SAP-Azure-3P Image SLES-SAP-BYOS-Azure Image SLES-SAP-BYOS-EC2 Image SLES-SAP-BYOS-GCE Image SLES-SAP-GCE Affected

References

Advisories & patches
PATCH https://git.kernel.org/stable/c/1cfa244f7198d325594e627574930b7b91df5bfe PATCH https://git.kernel.org/stable/c/56c5ef194f4509df63fc0f7a91ea5973ce479b1e PATCH https://git.kernel.org/stable/c/b41642c87716bbd09797b1e4ea7d904f06c39b7b PATCH https://git.kernel.org/stable/c/ddebb2a7677673cf4438a04e1a48b8ed6b0c8e9a PATCH https://git.kernel.org/stable/c/e7a375453cca2b8a0d2fa1b82b913f3fed7c0507 ADVISORY https://ubuntu.com/security/notices/USN-8126-1 ADVISORY https://vuldb.com/vuln/323663 ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:03600/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:03601/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:03633/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:03634/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20851/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20861/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20870/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20898/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20994/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:20996/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:21074/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:21139/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:21179/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:3725/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2025:3751/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20316/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20332/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20560/ REF https://git.kernel.org/stable/c/6b552ffd21f9be57806ade167a757f32dd66a98d

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy