CVE-2025-39834

Service interruption via leaked shared STC memory

Published Sep 16, 2025 · Updated Sep 16, 2025

Memory leakage in Linux kernel 6.12 through 6.16.4 and 6.17-rc1 through 6.17-rc3 allows local users to exhaust kernel memory. hws_action_get_shared_stc_nic allocates shared_stc for an invalid stc_type, then jumps to unlock_and_out without releasing the allocation. Low-privileged local access and an mlx5 device using hardware steering are required; repeated triggering can deplete memory and interrupt service.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leakage in Linux kernel 6.12 through 6.16.4 and 6.17-rc1 through 6.17-rc3 allows local users to exhaust kernel memory. hws_action_get_shared_stc_nic allocates shared_stc for an invalid stc_type, then jumps to unlock_and_out without releasing the allocation. Low-privileged local access and an mlx5 device using hardware steering are required; repeated triggering can deplete memory and interrupt service.

The record

CVE
CVE-2025-39834
Published
Sep 16, 2025
Updated
Sep 16, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=504e536d90104c850731840d3fbc95acf251f11b <051fd8576a2e4e95d5870c5c9f8679c5b16882e4
  2. Affected versionversion=504e536d90104c850731840d3fbc95acf251f11b <a630f83592cdad1253523a1b760cfe78fef6cd9c
  3. Affected versionversion=6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=504e536d90104c850731840d3fbc95acf251f11b <051fd8576a2e4e95d5870c5c9f8679c5b16882e4; version=504e536d90104c850731840d3fbc95acf251f11b <a630f83592cdad1253523a1b760cfe78fef6cd9c; version=6.12

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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