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NVD / CVE Program· CNA Linux

CVE-2025-39979: net/mlx5: fs, fix UAF in flow counter release

HighCVSS 7.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.14% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 3c77f6d244188c3fb11f6aec40bbfe884f1803b5, 6043819e707cefb1c9e59d6e431dcfa735c4f975.

Low priority for now. Upgrade to Linux Linux 3c77f6d244188c3fb11f6aec40bbfe884f1803b5, 6043819e707cefb1c9e59d6e431dcfa735c4f975 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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

Published
Oct 15, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 4th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 6.14affected
    • b581f4266928d3b5d1bbe711e39623d9a1696091 and later · before 3c77f6d244188c3fb11f6aec40bbfe884f1803b5affected · git
    • b581f4266928d3b5d1bbe711e39623d9a1696091 and later · before 6043819e707cefb1c9e59d6e431dcfa735c4f975affected · git
    • before 6.14not affected · semver
    • 6.16.10 and later · up to and including 6.16.*not affected · semver
    • 6.17 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-124.20.1.el10_16.12.0-124.20.1.el10_1
AlmaLinux:10kernel-docbefore 6.12.0-124.20.1.el10_16.12.0-124.20.1.el10_1
AlmaLinux:9kernelbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64kbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-corebefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-debugbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-debug-corebefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-debug-develbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-debug-devel-matchedbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-debug-modulesbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-debug-modules-corebefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-debug-modules-extrabefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-develbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-devel-matchedbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-modulesbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-modules-corebefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-64k-modules-extrabefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-abi-stablelistsbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-corebefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-cross-headersbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-debugbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-debug-corebefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-debug-develbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7
AlmaLinux:9kernel-debug-devel-matchedbefore 5.14.0-611.13.1.el9_75.14.0-611.13.1.el9_7

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-39977Oct 15, 2025 · futex: Prevent use-after-free during requeue-PI
    31Monitor
  • ← EarlierCVE-2025-39978Oct 15, 2025 · octeontx2-pf: Fix potential use after free in otx2_tc_add_flow()
    31Monitor
  • Later →CVE-2025-39980Oct 15, 2025 · nexthop: Forbid FDB status change while nexthop is in a group
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux3c77f6d244188c3fb11f6aec40bbfe884f1803b5Vendor (CNA)
Linux Linux6043819e707cefb1c9e59d6e431dcfa735c4f975Vendor (CNA)
almalinux:kernel5.14.0-611.13.1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k5.14.0-611.13.1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core5.14.0-611.13.1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-611.13.1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-611.13.1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-611.13.1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-611.13.1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-611.13.1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-611.13.1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-611.13.1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-abi-stablelists6.12.0-124.20.1.el10_1 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-doc6.12.0-124.20.1.el10_1 · AlmaLinux:10Package registry (OSV)
debian:linux6.16.10-1 · Debian:14Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-debug-devel0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-debug-devel-matched0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-debuginfo0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-debuginfo-common-aarch640:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:kernel-debuginfo-common-ppc64le0:6.12.0-124.20.1.el10_1 · Red Hat:enterprise_linux:10.1Package registry (OSV)
rocky linux:kernel0:6.12.0-124.20.1.el10_1 · Rocky Linux:10Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records