CVE-2025-39839

Kernel memory exposure and corruption via unchecked coded_len

Published Sep 19, 2025 · Updated Sep 19, 2025

Out-of-bounds access in Linux batman-adv allows attackers to expose or corrupt kernel memory via malformed network-coded packets. batadv_nc_skb_decode_packet trusts coded_len, subtracts the unicast header from destination headroom, and fails to verify the source skb payload before XORing. Reachability requires an active batman-adv mesh with network coding; crafted link-local traffic can disclose or overwrite kernel memory and interrupt the host.

CVSS severity8.8
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Linux batman-adv allows attackers to expose or corrupt kernel memory via malformed network-coded packets. batadv_nc_skb_decode_packet trusts coded_len, subtracts the unicast header from destination headroom, and fails to verify the source skb payload before XORing. Reachability requires an active batman-adv mesh with network coding; crafted link-local traffic can disclose or overwrite kernel memory and interrupt the host.

The record

CVE
CVE-2025-39839
Published
Sep 19, 2025
Updated
Sep 19, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125, T1499.004
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=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <1e36c6c8dc8023b4bbe9a16e819f9998b9b6a183
  2. Affected versionversion=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <20080709457bc1e920eb002483d7d981d9b2ac1c
  3. Affected versionversion=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <30fc47248f02b8a14a61df469e1da4704be1a19f
  4. Affected versionversion=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <5d334bce9fad58cf328d8fa14ea1fff855819863
  5. Affected versionversion=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <a67c6397fcb7e842d3c595243049940970541c48
  6. Affected versionversion=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <bb37252c9af1cb250f34735ee98f80b46be3cef1
  7. Affected versionversion=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <d77b6ff0ce35a6d0b0b7b9581bc3f76d041d4087
  8. Affected versionversion=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <dce6c2aa70e94c04c523b375dfcc664d7a0a560a
  9. Affected versionversion=3.10

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <1e36c6c8dc8023b4bbe9a16e819f9998b9b6a183; version=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <20080709457bc1e920eb002483d7d981d9b2ac1c; version=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <30fc47248f02b8a14a61df469e1da4704be1a19f; version=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <5d334bce9fad58cf328d8fa14ea1fff855819863; version=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <a67c6397fcb7e842d3c595243049940970541c48; version=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <bb37252c9af1cb250f34735ee98f80b46be3cef1; version=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <d77b6ff0ce35a6d0b0b7b9581bc3f76d041d4087; version=2df5278b0267c799f3e877e8eeddbb6e93cda0bb <dce6c2aa70e94c04c523b375dfcc664d7a0a560a; version=3.10

Published CVSS scores

8.8kernel.orgCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.

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No observations available

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

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

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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