Skip to content
Fencer Vulns
critical 9.8

CVE-2026-64391 in the critical feed json

ksmbd: use opener credentials for ADS I/O

published 2026-07-25 3 mo ago modified 2026-10-30 10 d ago also EUVD-2026-48935

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

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

ksmbd: use opener credentials for ADS I/O

Alternate data streams are stored as xattrs. Unlike regular file I/O, their read and write paths therefore call VFS xattr helpers which recheck inode permissions and LSM policy using the current task credentials.

Run ADS I/O with the credentials captured when the SMB handle was opened.

Patch / fix

  • Linux Linux 6.1.191, 6.6.160, 6.12.96, 6.18.39, 7.1.4, 7.2
  • linux Debian 13 6.12.96-1
  • linux Debian 14 7.1.4-1
  • linux-6.12 Debian 12 6.12.100-1~deb12u1

debian advisories DEBIAN-CVE-2026-64391

  • linux Ubuntu 24.04 LTS 6.8.0-147.147
  • linux Ubuntu 26.04 LTS 7.0.0-31.31
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1067.70
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1012.12
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1071.79
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1011.11
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1066.74
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1006.7

ubuntu advisories UBUNTU-CVE-2026-64391

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-source openSUSE Tumbleweed 7.1.7-1.1

opensuse advisories openSUSE-SU-2026:11476-1

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-2026-64391 updated cvss 5.3

kernel: ksmbd: use opener credentials for ADS I/O

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +2 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +9 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +30 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +84 more Red Hat Enterprise Linux 10 kernel 6.12.0-55.92.1.el10_0
    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

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% 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

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.