CVE-2025-39849

Kernel memory corruption via overlength Wi-Fi SSID

Published Sep 19, 2025 · Updated Sep 19, 2025

Heap overflow in Linux kernel cfg80211 allows physically proximate attackers to corrupt kernel memory using an overlength Wi-Fi SSID. The __cfg80211_connect_result() function copies ssid->datalen bytes from a cached beacon or probe response into a 32-byte SSID buffer without clamping the length. A rogue access point or injected 802.11 frame within radio range can overwrite adjacent kernel objects, disclose or alter kernel data, and crash the host.

CVSS severity8.8
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap overflow in Linux kernel cfg80211 allows physically proximate attackers to corrupt kernel memory using an overlength Wi-Fi SSID. The __cfg80211_connect_result() function copies ssid->datalen bytes from a cached beacon or probe response into a 32-byte SSID buffer without clamping the length. A rogue access point or injected 802.11 frame within radio range can overwrite adjacent kernel objects, disclose or alter kernel data, and crash the host.

The record

CVE
CVE-2025-39849
Published
Sep 19, 2025
Updated
Sep 19, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
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=6.3
  2. Affected versionversion=bf3c348c5fdcf00a7eeed04a1b83e454d2dca2e5
  3. Affected versionversion=c38c701851011c94ce3be1ccb3593678d2933fd8 <31229145e6ba5ace3e9391113376fa05b7831ede
  4. Affected versionversion=c38c701851011c94ce3be1ccb3593678d2933fd8 <5cb7cab7adf9b1e6a99e2081b0e30e9e59d07523
  5. Affected versionversion=c38c701851011c94ce3be1ccb3593678d2933fd8 <62b635dcd69c4fde7ce1de4992d71420a37e51e3
  6. Affected versionversion=c38c701851011c94ce3be1ccb3593678d2933fd8 <e472f59d02c82b511bc43a3f96d62ed08bf4537f
  7. Affected versionversion=dd43f8f90206054e7da7593de0a334fb2cd0ea88 <8e751d46336205abc259ed3990e850a9843fb649

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.3; version=bf3c348c5fdcf00a7eeed04a1b83e454d2dca2e5; version=c38c701851011c94ce3be1ccb3593678d2933fd8 <31229145e6ba5ace3e9391113376fa05b7831ede; version=c38c701851011c94ce3be1ccb3593678d2933fd8 <5cb7cab7adf9b1e6a99e2081b0e30e9e59d07523; version=c38c701851011c94ce3be1ccb3593678d2933fd8 <62b635dcd69c4fde7ce1de4992d71420a37e51e3; version=c38c701851011c94ce3be1ccb3593678d2933fd8 <e472f59d02c82b511bc43a3f96d62ed08bf4537f; version=dd43f8f90206054e7da7593de0a334fb2cd0ea88 <8e751d46336205abc259ed3990e850a9843fb649

Published CVSS scores

8.8Linux CNACVSS: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

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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