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Fencer Vulns
critical 9.8

CVE-2025-39975 in the critical feed json

smb: client: fix wrong index reference in smb2_compound_op()

published 2025-10-15 12 mo ago modified 2026-10-19 20 d ago also EUVD-2025-34597

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 40%
public exploits
0
none known

Summary

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

smb: client: fix wrong index reference in smb2_compound_op()

In smb2_compound_op(), the loop that processes each command's response uses wrong indices when accessing response bufferes.

This incorrect indexing leads to improper handling of command results. Also, if incorrectly computed index is greather than or equal to MAX_COMPOUND, it can cause out-of-bounds accesses.

Patch / fix

  • Linux Linux 6.6.109, 6.12.50, 6.14, 6.16.10, 6.17
  • linux Debian 13 6.12.57-1
  • linux Debian 14 6.16.10-1

debian advisories DEBIAN-CVE-2025-39975

  • linux Ubuntu 25.10 6.17.0-6.6
  • linux-aws Ubuntu 25.10 6.17.0-1003.3
  • linux-gcp Ubuntu 25.10 6.17.0-1003.3
  • linux-azure Ubuntu 25.10 6.17.0-1006.6
  • linux-raspi Ubuntu 25.10 6.17.0-1004.4
  • linux-riscv Ubuntu 25.10 6.17.0-6.6.1
  • linux-oracle Ubuntu 25.10 6.17.0-1003.3
  • linux-realtime Ubuntu 25.10 6.17.0-1002.3

ubuntu advisories UBUNTU-CVE-2025-39975

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

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-2025-39975 updated cvss 5.8

kernel: smb: client: fix wrong index reference in smb2_compound_op()

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-selftests-internal Red Hat Enterprise Linux 10 kernel
    affected: 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 Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 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

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% 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.