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Fencer Vulns
critical 9.8

CVE-2026-46195 in the critical feed json

smb: client: validate dacloffset before building DACL pointers

published 2026-05-28 5 mo ago modified 2026-10-19 20 d ago also EUVD-2026-32822

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits
0
none known

Summary

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

smb: client: validate dacloffset before building DACL pointers

parse_sec_desc(), build_sec_desc(), and the chown path in id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd before proving a DACL header fits inside the returned security descriptor.

On 32-bit builds a malicious server can return dacloffset near U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip past the later pointer-based bounds checks. build_sec_desc() and id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped pointer in the chmod/chown rewrite paths.

Validate dacloffset numerically before building any DACL pointer and reuse the same helper at the three DACL entry points.

Patch / fix

  • Linux Linux 5.15.210, 6.1.176, 6.6.140, 6.12.88, 6.18.30, 7.0.7, 7.1
  • Red Hat Red Hat Enterprise Linux 8 0:4.18.0-553.126.1.el8_10, 0:4.18.0-553.126.1.rt7.467.el8_10
  • Red Hat Red Hat Enterprise Linux 9 0:5.14.0-687.12.1.el9_8
  • linux Debian 12 6.1.176-1
  • linux Debian 13 6.12.88-1
  • linux Debian 14 7.0.7-1

debian advisories DEBIAN-CVE-2026-46195

  • linux Ubuntu 22.04 LTS 5.15.0-185.195
  • linux Ubuntu 24.04 LTS 6.8.0-134.134
  • linux Ubuntu 25.10 6.17.0-40.40
  • linux Ubuntu 26.04 LTS 7.0.0-27.27
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1111.118
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1060.63
  • linux-aws Ubuntu 25.10 6.17.0-1019.19
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1008.8

ubuntu advisories UBUNTU-CVE-2026-46195

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-rt RHEL 8 4.18.0-553.126.1.rt7.467.el8_10
  • kernel-rt-kvm RHEL 8 4.18.0-553.126.1.rt7.467.el8_10
  • kernel-rt-core RHEL 8 4.18.0-553.126.1.rt7.467.el8_10
  • kernel-rt-modules RHEL 8 4.18.0-553.126.1.rt7.467.el8_10
  • kernel-rt-debug-kvm RHEL 8 4.18.0-553.126.1.rt7.467.el8_10
  • kernel-rt-debug-core RHEL 8 4.18.0-553.126.1.rt7.467.el8_10
  • kernel-rt-debug-modules RHEL 8 4.18.0-553.126.1.rt7.467.el8_10
  • kernel-rt-modules-extra RHEL 8 4.18.0-553.126.1.rt7.467.el8_10

red hat advisories RHSA-2026:21745RHSA-2026:21706RHSA-2026:21556

  • 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-2026:5121-1SUSE-SU-2026:4254-1SUSE-SU-2026:23887-1SUSE-SU-2026:23902-1SUSE-SU-2026:23897-1SUSE-SU-2026:23881-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1openSUSE-SU-2026:10954-1

  • kernel AlmaLinux 9 5.14.0-687.12.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.12.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.12.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.12.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.12.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.12.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.12.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.12.1.el9_8

almalinux advisories ALSA-2026:21556ALSA-2026:21706ALSA-2026:21745

  • kernel Azure Linux 3.0 6.6.141.1-1

azure linux advisories AZL-89013

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2026-46195 updated cvss 7.5

kernel: smb: client: validate dacloffset before building DACL pointers

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux 10 kernel
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.12.1.el9_8, perf 5.14.0-687.12.1.el9_8, rtla 5.14.0-687.12.1.el9_8, python3-perf 5.14.0-687.12.1.el9_8, kernel-devel-matched 5.14.0-687.12.1.el9_8, kernel-64k-devel-matched 5.14.0-687.12.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:21556
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.126.1.el8_10, kernel 4.18.0-553.126.1.el8_10, bpftool 4.18.0-553.126.1.el8_10, kernel-core 4.18.0-553.126.1.el8_10, kernel-tools 4.18.0-553.126.1.el8_10, python3-perf 4.18.0-553.126.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:21706
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.12.1.el9_8, kernel-64k 5.14.0-687.12.1.el9_8, kernel-core 5.14.0-687.12.1.el9_8, kernel-tools 5.14.0-687.12.1.el9_8, kernel-modules 5.14.0-687.12.1.el9_8, kernel-64k-core 5.14.0-687.12.1.el9_8, +29 more
    fixed: vendor fix RHSA-2026:21556
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) kpatch-patch-5_14_0-427_146_1 1-4.el9_4, kpatch-patch-5_14_0-427_84_1 1-20.el9_4, kpatch-patch-5_14_0-427_100_1 1-18.el9_4, kpatch-patch-5_14_0-427_113_1 1-16.el9_4, kpatch-patch-5_14_0-427_126_1 1-13.el9_4
    fixed: vendor fix RHSA-2026:96090
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kpatch-patch-5_14_0-570_135_1 1-4.el9_6, kpatch-patch-5_14_0-570_39_1 1-19.el9_6, kpatch-patch-5_14_0-570_66_1 1-18.el9_6, kpatch-patch-5_14_0-570_94_1 1-16.el9_6, kpatch-patch-5_14_0-570_116_1 1-13.el9_6
    fixed: vendor fix RHSA-2026:96091
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.12.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.12.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.12.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.12.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.12.1.el9_8
    fixed: vendor fix RHSA-2026:21556
show 5 more
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.126.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.126.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.126.1.el8_10
    fixed: vendor fix RHSA-2026:21706
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-kvm 4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-core 4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-modules 4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-debug-kvm 4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-debug-core 4.18.0-553.126.1.rt7.467.el8_10, +4 more
    fixed: vendor fix RHSA-2026:21745
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.12.1.el9_8, kernel-rt-64k 5.14.0-687.12.1.el9_8, kernel-rt-core 5.14.0-687.12.1.el9_8, kernel-rt-modules 5.14.0-687.12.1.el9_8, kernel-rt-64k-core 5.14.0-687.12.1.el9_8, kernel-rt-debug-core 5.14.0-687.12.1.el9_8, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.12.1.el9_8, kernel-rt-core 5.14.0-687.12.1.el9_8, kernel-rt-modules 5.14.0-687.12.1.el9_8, kernel-rt-debug-core 5.14.0-687.12.1.el9_8, kernel-rt-modules-core 5.14.0-687.12.1.el9_8, kernel-rt-debug-modules 5.14.0-687.12.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:21556
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-core 4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-modules 4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-debug-core 4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-debug-modules 4.18.0-553.126.1.rt7.467.el8_10, kernel-rt-modules-extra 4.18.0-553.126.1.rt7.467.el8_10, +2 more
    fixed: vendor fix RHSA-2026:21745
  • 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
    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-26-295-16 updated cvss 9.8

Siemens SIMATIC S7-1500 TM MFP

  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
    affected: mitigation, no fix available

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
yes
Technical impact
total
Assessed
24 d ago

Exploit prediction

0.68% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADP 3.1 7.5 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 7.5 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Classification

Weakness
Technology feeds

References

Sources

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.