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Fencer Vulns
high 7.8

CVE-2025-39979 json

net/mlx5: fs, fix UAF in flow counter release

published 2025-10-15 12 mo ago modified 2026-10-19 20 d ago also EUVD-2025-34593

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

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

net/mlx5: fs, fix UAF in flow counter release

Fix a kernel trace [1] caused by releasing an HWS action of a local flow counter in mlx5_cmd_hws_delete_fte(), where the HWS action refcount and mutex were not initialized and the counter struct could already be freed when deleting the rule.

Fix it by adding the missing initializations and adding refcount for the local flow counter struct.

[1] Kernel log: Call Trace: <TASK> dump_stack_lvl+0x34/0x48 mlx5_fs_put_hws_action.part.0.cold+0x21/0x94 [mlx5_core] mlx5_fc_put_hws_action+0x96/0xad [mlx5_core] mlx5_fs_destroy_fs_actions+0x8b/0x152 [mlx5_core] mlx5_cmd_hws_delete_fte+0x5a/0xa0 [mlx5_core] del_hw_fte+0x1ce/0x260 [mlx5_core] mlx5_del_flow_rules+0x12d/0x240 [mlx5_core] ? ttwu_queue_wakelist+0xf4/0x110 mlx5_ib_destroy_flow+0x103/0x1b0 [mlx5_ib] uverbs_free_flow+0x20/0x50 [ib_uverbs] destroy_hw_idr_uobject+0x1b/0x50 [ib_uverbs] uverbs_destroy_uobject+0x34/0x1a0 [ib_uverbs] uobj_destroy+0x3c/0x80 [ib_uverbs] ib_uverbs_run_method+0x23e/0x360 [ib_uverbs] ? uverbs_finalize_object+0x60/0x60 [ib_uverbs] ib_uverbs_cmd_verbs+0x14f/0x2c0 [ib_uverbs] ? do_tty_write+0x1a9/0x270 ? file_tty_write.constprop.0+0x98/0xc0 ? new_sync_write+0xfc/0x190 ib_uverbs_ioctl+0xd7/0x160 [ib_uverbs] __x64_sys_ioctl+0x87/0xc0 do_syscall_64+0x59/0x90

Patch / fix

  • Linux Linux 6.16.10, 6.17
  • linux Debian 14 6.16.10-1

debian advisories DEBIAN-CVE-2025-39979

  • 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-2025-39979

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 RHEL 9 5.14.0-611.13.1.el9_7
  • rv RHEL 9 5.14.0-611.13.1.el9_7
  • perf RHEL 9 5.14.0-611.13.1.el9_7
  • rtla RHEL 9 5.14.0-611.13.1.el9_7
  • libperf RHEL 9 5.14.0-611.13.1.el9_7
  • kernel-rt RHEL 9 5.14.0-611.13.1.el9_7
  • kernel-64k RHEL 9 5.14.0-611.13.1.el9_7
  • kernel-core RHEL 9 5.14.0-611.13.1.el9_7

red hat advisories RHSA-2025:22865RHSA-2025:22854

  • kernel-rt Linux Micro 6.2 6.12.0-160000.7.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.7.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.7.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.7.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1.160000.2.4
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.7.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.7.1
  • kernel-kvmsmall SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.7.1

suse advisories SUSE-SU-2025:21080-1SUSE-SU-2025:21147-1SUSE-SU-2025:21180-1SUSE-SU-2026:20561-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.7.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.7.1

opensuse advisories openSUSE-SU-2025:20091-1

  • kernel-abi-stablelists AlmaLinux 10 6.12.0-124.20.1.el10_1
  • kernel AlmaLinux 9 5.14.0-611.13.1.el9_7
  • rv AlmaLinux 9 5.14.0-611.13.1.el9_7
  • perf AlmaLinux 9 5.14.0-611.13.1.el9_7
  • rtla AlmaLinux 9 5.14.0-611.13.1.el9_7
  • libperf AlmaLinux 9 5.14.0-611.13.1.el9_7
  • kernel-rt AlmaLinux 9 5.14.0-611.13.1.el9_7
  • kernel-64k AlmaLinux 9 5.14.0-611.13.1.el9_7

almalinux advisories ALSA-2025:22854ALSA-2025:22865

  • kernel Rocky Linux 10 6.12.0-124.20.1.el10_1
  • kernel Rocky Linux 9 5.14.0-611.13.1.el9_7

rocky linux advisories RLSA-2025:22854RLSA-2025:22865

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-2025-39979 updated cvss 7.6

kernel: net/mlx5: fs, fix UAF in flow counter release

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: workaround, no fix planned “Out of support scope”
  • 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 available
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-611.13.1.el9_7, perf 5.14.0-611.13.1.el9_7, rtla 5.14.0-611.13.1.el9_7, python3-perf 5.14.0-611.13.1.el9_7, kernel-devel-matched 5.14.0-611.13.1.el9_7, kernel-64k-devel-matched 5.14.0-611.13.1.el9_7, +7 more
    fixed: vendor fix RHSA-2025:22865
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-124.20.1.el10_1, perf 6.12.0-124.20.1.el10_1, rtla 6.12.0-124.20.1.el10_1, python3-perf 6.12.0-124.20.1.el10_1, kernel-devel-matched 6.12.0-124.20.1.el10_1, kernel-64k-devel-matched 6.12.0-124.20.1.el10_1, +7 more
    fixed: vendor fix RHSA-2025:22854
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-611.13.1.el9_7, kernel-64k 5.14.0-611.13.1.el9_7, kernel-core 5.14.0-611.13.1.el9_7, kernel-tools 5.14.0-611.13.1.el9_7, kernel-modules 5.14.0-611.13.1.el9_7, kernel-64k-core 5.14.0-611.13.1.el9_7, +27 more
    fixed: vendor fix RHSA-2025:22865
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-124.20.1.el10_1, kernel-64k 6.12.0-124.20.1.el10_1, kernel-core 6.12.0-124.20.1.el10_1, kernel-tools 6.12.0-124.20.1.el10_1, kernel-modules 6.12.0-124.20.1.el10_1, kernel-64k-core 6.12.0-124.20.1.el10_1, +28 more
    fixed: vendor fix RHSA-2025:22854
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-611.13.1.el9_7, kernel-debuginfo-common-s390x 5.14.0-611.13.1.el9_7, kernel-debuginfo-common-x86_64 5.14.0-611.13.1.el9_7, kernel-debuginfo-common-aarch64 5.14.0-611.13.1.el9_7, kernel-debuginfo-common-ppc64le 5.14.0-611.13.1.el9_7
    fixed: vendor fix RHSA-2025:22865
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-124.20.1.el10_1, kernel-debuginfo-common-s390x 6.12.0-124.20.1.el10_1, kernel-debuginfo-common-x86_64 6.12.0-124.20.1.el10_1, kernel-debuginfo-common-aarch64 6.12.0-124.20.1.el10_1, kernel-debuginfo-common-ppc64le 6.12.0-124.20.1.el10_1
    fixed: vendor fix RHSA-2025:22854
show 5 more
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-611.13.1.el9_7, kernel-rt-64k 5.14.0-611.13.1.el9_7, kernel-rt-core 5.14.0-611.13.1.el9_7, kernel-rt-modules 5.14.0-611.13.1.el9_7, kernel-rt-64k-core 5.14.0-611.13.1.el9_7, kernel-rt-debug-core 5.14.0-611.13.1.el9_7, +14 more
    fixed: vendor fix RHSA-2025:22865
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-124.20.1.el10_1, kernel-rt-64k 6.12.0-124.20.1.el10_1, kernel-rt-core 6.12.0-124.20.1.el10_1, kernel-rt-modules 6.12.0-124.20.1.el10_1, kernel-rt-64k-core 6.12.0-124.20.1.el10_1, kernel-rt-debug-core 6.12.0-124.20.1.el10_1, +14 more
    fixed: vendor fix RHSA-2025:22854
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-611.13.1.el9_7, kernel-rt-core 5.14.0-611.13.1.el9_7, kernel-rt-modules 5.14.0-611.13.1.el9_7, kernel-rt-debug-core 5.14.0-611.13.1.el9_7, kernel-rt-modules-core 5.14.0-611.13.1.el9_7, kernel-rt-debug-modules 5.14.0-611.13.1.el9_7, +4 more
    fixed: vendor fix RHSA-2025:22865
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-124.20.1.el10_1, kernel-rt-core 6.12.0-124.20.1.el10_1, kernel-rt-modules 6.12.0-124.20.1.el10_1, kernel-rt-debug-core 6.12.0-124.20.1.el10_1, kernel-rt-modules-core 6.12.0-124.20.1.el10_1, kernel-rt-debug-modules 6.12.0-124.20.1.el10_1, +4 more
    fixed: vendor fix RHSA-2025:22854
  • 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 SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
24 d ago

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/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.