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

smb: client: split cached_fid bitfields to avoid shared-byte RMW races

is_open, has_lease and on_list are stored in the same bitfield byte in
struct cached_fid but are updated in different code paths that may run
concurrently. Bitfield assignments generate byte read–modify–write
operations (e.g. `orb $mask, addr` on x86_64), so updating one flag can
restore stale values of the others.

A possible interleaving is:
CPU1: load old byte (has_lease=1, on_list=1)
CPU2: clear both flags (store 0)
CPU1: RMW store (old | IS_OPEN) -> reintroduces cleared bits

To avoid this class of races, convert these flags to separate bool
fields.
Published: 2026-02-18
Score: 8.8 High
EPSS: < 1% Very Low
KEV: No
Impact: Data corruption and potential denial of service within the Linux SMB client
Action: Immediate Patch
AI Analysis

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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 DLA Debian DLA DLA-4499-1 linux-6.1 security update
Debian DSA Debian DSA DSA-6141-1 linux security update
Debian DSA Debian DSA DSA-6163-1 linux security update
History

Wed, 15 Apr 2026 17:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Thu, 02 Apr 2026 15:15:00 +0000

Type Values Removed Values Added
Metrics 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'}

cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}


Tue, 17 Mar 2026 21:30:00 +0000

Type Values Removed Values Added
Weaknesses NVD-CWE-noinfo
Metrics cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

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'}


Mon, 23 Feb 2026 03:30:00 +0000


Thu, 19 Feb 2026 16:15:00 +0000


Thu, 19 Feb 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate


Wed, 18 Feb 2026 15:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: smb: client: split cached_fid bitfields to avoid shared-byte RMW races is_open, has_lease and on_list are stored in the same bitfield byte in struct cached_fid but are updated in different code paths that may run concurrently. Bitfield assignments generate byte read–modify–write operations (e.g. `orb $mask, addr` on x86_64), so updating one flag can restore stale values of the others. A possible interleaving is: CPU1: load old byte (has_lease=1, on_list=1) CPU2: clear both flags (store 0) CPU1: RMW store (old | IS_OPEN) -> reintroduces cleared bits To avoid this class of races, convert these flags to separate bool fields.
Title smb: client: split cached_fid bitfields to avoid shared-byte RMW races
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: 2026-05-11T22:02:50.386Z

Reserved: 2026-01-13T15:37:45.988Z

Link: CVE-2026-23230

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2026-02-18T16:22:32.807

Modified: 2026-04-02T15:16:24.460

Link: CVE-2026-23230

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-02-18T00:00:00Z

Links: CVE-2026-23230 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-15T17:15:10Z

Weaknesses