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Fencer Vulns
critical 9.4

CVE-2025-40099 in the critical feed json

cifs: parse_dfs_referrals: prevent oob on malformed input

published 2025-10-30 12 mo ago modified 2026-10-19 20 d ago also EUVD-2025-36979

cvss
9.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits
0
none known

Summary

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

cifs: parse_dfs_referrals: prevent oob on malformed input

Malicious SMB server can send invalid reply to FSCTL_DFS_GET_REFERRALS

- reply smaller than sizeof(struct get_dfs_referral_rsp) - reply with number of referrals smaller than NumberOfReferrals in the header

Processing of such replies will cause oob.

Return -EINVAL error on such replies to prevent oob-s.

Patch / fix

  • Linux Linux 6.1.158, 6.6.114, 6.12.55, 6.17.5, 6.18
  • linux Debian 12 6.1.158-1
  • linux Debian 13 6.12.57-1
  • linux Debian 14 6.17.6-1

debian advisories DEBIAN-CVE-2025-40099

  • linux Ubuntu 24.04 LTS 6.8.0-106.106
  • linux Ubuntu 25.10 6.17.0-14.14
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1050.53
  • linux-aws Ubuntu 25.10 6.17.0-1007.7
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1052.55
  • linux-gcp Ubuntu 25.10 6.17.0-1007.7
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1048.53
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1049.49

ubuntu advisories UBUNTU-CVE-2025-40099

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 6.4.0-150700.53.34.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.34.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.34.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.34.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.34.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1.150700.17.23.1

suse advisories SUSE-SU-2026:1081-1SUSE-SU-2026:1078-1SUSE-SU-2026:1041-1SUSE-SU-2026:20873-1SUSE-SU-2026:20838-1SUSE-SU-2026:20931-1

  • 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-2026:20416-1openSUSE-SU-2026:10301-1openSUSE-SU-2025:15702-1

  • kernel Azure Linux 3.0 6.6.117.1-1

azure linux advisories AZL-69436

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-2025-40099 updated cvss 5.5

kernel: cifs: parse_dfs_referrals: prevent oob on malformed input

  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more 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
    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 SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
24 d ago

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H

Affected products

  • Linux Linux

Classification

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.