high 8.8

CVE-2026-23230 json

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

published 2026-02-18 8 mo ago modified 2026-10-19 20 d ago also EUVD-2026-7671

cvss: 8.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits: 0; none known

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

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.

Patch / fix

fixed in 2 distros 4 links 6

Linux Linux 6.1.164, 6.6.125, 6.12.72, 6.18.11, 6.19.1, 7.0
Siemens RUGGEDCOM RST2428P V4.0

debian ubuntu suse opensuse

linux Debian 12 6.1.164-1
linux Debian 13 6.12.73-1
linux Debian 14 6.18.12-1

debian advisories DEBIAN-CVE-2026-23230

linux Ubuntu 24.04 LTS 6.8.0-134.134
linux-aws Ubuntu 24.04 LTS 6.8.0-1060.63
linux-gcp Ubuntu 24.04 LTS 6.8.0-1063.69
linux-gke Ubuntu 24.04 LTS 6.8.0-1058.64
linux-ibm Ubuntu 24.04 LTS 6.8.0-1060.61
linux-azure Ubuntu 24.04 LTS 6.8.0-1063.71
linux-gkeop Ubuntu 24.04 LTS 6.8.0-1045.48
linux-raspi Ubuntu 24.04 LTS 6.8.0-1060.64

ubuntu advisories UBUNTU-CVE-2026-23230

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1
kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.81.1
kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.81.1
kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1
kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1.150700.17.45.1

suse advisories SUSE-SU-2026:4254-1 SUSE-SU-2026:4369-1 SUSE-SU-2026:4120-1 SUSE-SU-2026:23481-1 SUSE-SU-2026:23477-1 SUSE-SU-2026:23529-1

kernel-rt openSUSE Leap 16.0 6.12.0-160000.27.1
dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.27.1
kernel-64kb openSUSE Leap 16.0 6.12.0-160000.27.1
kernel-syms openSUSE Leap 16.0 6.12.0-160000.27.1
kernel-azure openSUSE Leap 16.0 6.12.0-160000.27.1
kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.27.1
kernel-source openSUSE Leap 16.0 6.12.0-160000.27.1
kernel-default openSUSE Leap 16.0 6.12.0-160000.27.1

opensuse advisories openSUSE-SU-2026:20416-1 openSUSE-SU-2026:10387-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-23230 updated 2026-11-05 cvss 6.3

kernel: Linux kernel: Denial of Service in SMB client due to race condition

Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
affected: workaround, no fix available, no fix planned “Out of support scope”
Red Hat Enterprise Linux 10 kernel
affected: workaround, no fix available “Fix deferred”
Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-26-188-05 updated 2026-07-07 cvss 8.8

Siemens SINEC OS

Siemens RUGGEDCOM RST2428P (6GK6242-6PA00) < 4.0
affected: fixed in V4.0 support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 24 d ago (2026-10-16)

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD	3.1	5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

Linux Linux
Siemens RUGGEDCOM RST2428P

Classification

Weakness

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2026-23230
NVD CVE-2026-23230

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary