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

tracing: Fix WARN_ON in tracing_buffers_mmap_close

When a process forks, the child process copies the parent's VMAs but the
user_mapped reference count is not incremented. As a result, when both the
parent and child processes exit, tracing_buffers_mmap_close() is called
twice. On the second call, user_mapped is already 0, causing the function to
return -ENODEV and triggering a WARN_ON.

Normally, this isn't an issue as the memory is mapped with VM_DONTCOPY set.
But this is only a hint, and the application can call
madvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the
application does that, it can trigger this issue on fork.

Fix it by incrementing the user_mapped reference count without re-mapping
the pages in the VMA's open callback.
Published: 2026-03-25
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Double close of tracing buffers on fork can trigger WARN_ON and return -ENODEV, but does not permit code execution.
Action: Apply Patch
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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-6238-1 linux security update
History

Fri, 24 Apr 2026 16:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-617
CPEs cpe:2.3:o:linux:linux_kernel:6.10:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 3.3, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L'}

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}


Thu, 26 Mar 2026 12:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-398

Thu, 26 Mar 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-911
References
Metrics threat_severity

None

cvssV3_1

{'score': 3.3, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L'}

threat_severity

Low


Wed, 25 Mar 2026 22:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-398

Wed, 25 Mar 2026 10:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: tracing: Fix WARN_ON in tracing_buffers_mmap_close When a process forks, the child process copies the parent's VMAs but the user_mapped reference count is not incremented. As a result, when both the parent and child processes exit, tracing_buffers_mmap_close() is called twice. On the second call, user_mapped is already 0, causing the function to return -ENODEV and triggering a WARN_ON. Normally, this isn't an issue as the memory is mapped with VM_DONTCOPY set. But this is only a hint, and the application can call madvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the application does that, it can trigger this issue on fork. Fix it by incrementing the user_mapped reference count without re-mapping the pages in the VMA's open callback.
Title tracing: Fix WARN_ON in tracing_buffers_mmap_close
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T22:05:45.422Z

Reserved: 2026-01-13T15:37:46.007Z

Link: CVE-2026-23380

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2026-03-25T11:16:38.017

Modified: 2026-04-24T16:28:47.850

Link: CVE-2026-23380

cve-icon Redhat

Severity : Low

Publid Date: 2026-03-25T00:00:00Z

Links: CVE-2026-23380 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-28T17:00:13Z

Weaknesses