CVE-2025-39813

Medium

In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix potential warning in trace_printk_seq during ftrace_dump When calling ftrace_dump_one() concurrently with reading trace_pipe, a WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a race condition. The issue occurs because: CPU0 (ftrace_dump) CPU1 (reader) echo z > /proc/sysrq-trigger !trace_empty(&iter) trace_iterator_reset(&iter) <- len = size = 0 cat /sys/kernel/tracing/trace_pipe trace_find_next_entry_inc(&iter) __find_next_entry ring_buffer_empty_cpu <- all empty return NULL trace_printk_seq(&iter.seq) WARN_ON_ONCE(s->seq.len >= s->seq.size) In the context between trace_empty() and trace_find_next_entry_inc() during ftrace_dump, the ring buffer data was consumed by other readers. This caused trace_find_next_entry_inc to return NULL, failing to populate `iter.seq`. At this point, due to the prior trace_iterator_reset, both `iter.seq.len` and `iter.seq.size` were set to 0. Since they are equal, the WARN_ON_ONCE condition is triggered. Move the trace_printk_seq() into the if block that checks to make sure the return value of trace_find_next_entry_inc() is non-NULL in ftrace_dump_one(), ensuring the 'iter.seq' is properly populated before subsequent operations.

Package Linux Kernel
Published 2025-09-16
Last modified 2026-05-12
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

4.7

out of 10
Medium
Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness type

CWE-362

CVE-2025-39813 is a Race Condition vulnerability

What is Race Condition?

The product contains a code sequence that can run concurrently with other code, creating unexpected states. Learn more on MITRE CWE

Affected versions

Linux kernel versions 2.6.28 and later are affected. Fixed in 5.4.298, 5.10.242, 5.15.191, 6.1.150, 6.6.104, 6.12.45, 6.16.5, 6.17 and their respective stable series.

Affected from
≥ 2.6.28
Fixed in
✓ 5.4.298 5.4.x ✓ 5.10.242 5.10.x ✓ 5.15.191 5.15.x ✓ 6.1.150 6.1.x ✓ 6.6.104 6.6.x ✓ 6.12.45 6.12.x ✓ 6.16.5 6.16.x ✓ 6.17

References

The following references provide additional information about CVE-2025-39813 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

8 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2025-39813?

    CVE-2025-39813 is a Medium severity Linux kernel vulnerability with a CVSS score of 4.7 out of 10 , classified as a Race Condition flaw (CWE-362) . It affects Linux kernel versions from 2.6.28 onward and has been patched in 5.4.298, 5.10.242, 5.15.191 and others. CVE-2025-39813 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-39813?

    CVE-2025-39813 has a CVSS score of 4.7 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2025-39813?

    Yes — CVE-2025-39813 has been patched. Fixed versions include 5.4.298, 5.10.242, 5.15.191 and others. If you are running Linux kernel 2.6.28 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-39813 actively exploited?

    No — CVE-2025-39813 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is Race Condition (CWE-362)?

    The product contains a code sequence that can run concurrently with other code, creating unexpected states. View CWE-362 on MITRE CWE →

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