CVE-2025-39864

Kernel memory corruption via shared beacon data free

Published Sep 19, 2025 · Updated Sep 19, 2025

Use-after-free in cfg80211 in affected Linux kernel releases allows adjacent attackers to corrupt kernel memory through Wi-Fi frames. cfg80211_update_known_bss() frees the last beacon elements even when hidden_beacon_bss still shares them, leaving cmp_bss() to access freed data. An attacker within wireless range needs no credentials or user interaction; exploitation can expose or alter kernel memory or crash the system.

CVSS severity8.8
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in cfg80211 in affected Linux kernel releases allows adjacent attackers to corrupt kernel memory through Wi-Fi frames. cfg80211_update_known_bss() frees the last beacon elements even when hidden_beacon_bss still shares them, leaving cmp_bss() to access freed data. An attacker within wireless range needs no credentials or user interaction; exploitation can expose or alter kernel memory or crash the system.

The record

CVE
CVE-2025-39864
Published
Sep 19, 2025
Updated
Sep 19, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 19, 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=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <26e84445f02ce6b2fe5f3e0e28ff7add77f35e08
  2. Affected versionversion=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <5b7ae04969f822283a95c866967e42b4d75e0eef
  3. Affected versionversion=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <6854476d9e1aeaaf05ebc98d610061c2075db07d
  4. Affected versionversion=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <912c4b66bef713a20775cfbf3b5e9bd71525c716
  5. Affected versionversion=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <a8bb681e879ca3c9f722aa08d3d7ae41c42a8807
  6. Affected versionversion=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <a97a9791e455bb0cd5e7a38b5abcb05523d4e21c
  7. Affected versionversion=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <b7d08929178c16398278613df07ad65cf63cce9d
  8. Affected versionversion=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <ff040562c10a540b8d851f7f4145fa112977f853
  9. Affected versionversion=5.4

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <26e84445f02ce6b2fe5f3e0e28ff7add77f35e08; version=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <5b7ae04969f822283a95c866967e42b4d75e0eef; version=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <6854476d9e1aeaaf05ebc98d610061c2075db07d; version=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <912c4b66bef713a20775cfbf3b5e9bd71525c716; version=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <a8bb681e879ca3c9f722aa08d3d7ae41c42a8807; version=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <a97a9791e455bb0cd5e7a38b5abcb05523d4e21c; version=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <b7d08929178c16398278613df07ad65cf63cce9d; version=3ab8227d3e7d1d2bf1829675d3197e3cb600e9f6 <ff040562c10a540b8d851f7f4145fa112977f853; version=5.4

Published CVSS scores

8.8LinuxCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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