CVE-2025-39839: debian linux Out-of-bounds Read — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: batman-adv: fix OOB read/write in network-coding decode batadv_nc_skb_decode_packet() trusts coded_len and checks only against skb->len. XOR starts at sizeof(struct batadv_unicast_packet), reducing payload headroom, and the source skb length is not verified, allowing an out-of-bounds read and a small out-of-bounds write. Validate that coded_len fits within the payload area of both destination and source sk_buffs before XORing.

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CVSS v3.1 Score

7.1

HIGH

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

Weakness Type (CWE)

CWE-125 Out-of-bounds Read

Affected Products

Vendor	Product	Versions
linux	linux_kernel	3.10 — 5.4.299
linux	linux_kernel	5.5 — 5.10.243
linux	linux_kernel	5.11 — 5.15.192
linux	linux_kernel	5.16 — 6.1.151
linux	linux_kernel	6.2 — 6.6.105
linux	linux_kernel	6.7 — 6.12.46
linux	linux_kernel	6.13 — 6.16.6
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
debian	debian_linux	All

References

Advisories & Patches

https://git.kernel.org/stable/c/1e36c6c8dc8023b4bbe9a16e819f9998b9b6a183 https://git.kernel.org/stable/c/20080709457bc1e920eb002483d7d981d9b2ac1c https://git.kernel.org/stable/c/30fc47248f02b8a14a61df469e1da4704be1a19f https://git.kernel.org/stable/c/5d334bce9fad58cf328d8fa14ea1fff855819863 https://git.kernel.org/stable/c/a67c6397fcb7e842d3c595243049940970541c48 https://git.kernel.org/stable/c/bb37252c9af1cb250f34735ee98f80b46be3cef1 https://git.kernel.org/stable/c/d77b6ff0ce35a6d0b0b7b9581bc3f76d041d4087 https://git.kernel.org/stable/c/dce6c2aa70e94c04c523b375dfcc664d7a0a560a

Other References

https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html https://cert-portal.siemens.com/productcert/html/ssa-032379.html https://cert-portal.siemens.com/productcert/html/ssa-089022.html

Frequently Asked Questions

What is CVE-2025-39839? +

In the Linux kernel, the following vulnerability has been resolved: batman-adv: fix OOB read/write in network-coding decode batadv_nc_skb_decode_packet() trusts coded_len and checks only against skb->len. XOR starts at sizeof(struct batadv_unicast_packet), reducing payload headroom, and the source skb length is not verified, allowing an out-of-bounds read and a small out-of-bounds write. Validate that coded_len fits within the payload area of both destination and source sk_buffs before XORing. It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2025-39839? +

CVE-2025-39839 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-39839? +

CVE-2025-39839 affects products from debian, linux, specifically: debian_linux, linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-39839? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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