CVE-2021-42008

HIGH

Linux Kernel 2.6.12-4.4.282 - Authenticated Out-of-bounds Write in 6pack Decode Function

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 3 public exploits for CVE-2021-42008. PoCs published by 0xdevil, numanturle, WhatsWrongAndWhy.

AI-analyzed exploit summary This is a working exploit for CVE-2021-42008, targeting a 16-year-old vulnerability in the Linux 6pack driver. The exploit leverages userfaultfd and message queue manipulation to achieve local privilege escalation (LPE) on Debian 11 with kernel 5.10.0-8-amd64.

Description

The decode_data function in drivers/net/hamradio/6pack.c in the Linux kernel before 5.13.13 has a slab out-of-bounds write. Input from a process that has the CAP_NET_ADMIN capability can lead to root access.

Exploits (3)

nomisec WORKING POC 31 stars
by 0xdevil · poc
https://github.com/0xdevil/CVE-2021-42008

This is a working exploit for CVE-2021-42008, targeting a 16-year-old vulnerability in the Linux 6pack driver. The exploit leverages userfaultfd and message queue manipulation to achieve local privilege escalation (LPE) on Debian 11 with kernel 5.10.0-8-amd64.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Complex
Reliability
Racy
Target: Linux kernel 5.10.0-8-amd64 (6pack driver)
No auth needed
Prerequisites: Linux kernel with 6pack driver enabled · User namespace access · Debian 11 or similar environment
mistral-large-3 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 2 stars
by numanturle · poc
https://github.com/numanturle/CVE-2021-42008

This is a working exploit for CVE-2021-42008, targeting a 16-year-old vulnerability in the Linux 6pack driver. The exploit leverages userfaultfd and message queue manipulation to achieve local privilege escalation (LPE) on Debian 11 with kernel 5.10.0-8-amd64.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Complex
Reliability
Reliable
Target: Linux kernel 5.10.0-8-amd64 (6pack driver)
No auth needed
Prerequisites: Linux system with 6pack driver loaded · Kernel version 5.10.0-8-amd64 or similar vulnerable version
mistral-large-3 · analyzed Feb 16, 2026 Full analysis →
nomisec TROJAN
by WhatsWrongAndWhy · poc
https://github.com/WhatsWrongAndWhy/CVE-2021-42008

The provided file labeled as CVE-2021-42008 is not a legitimate exploit PoC but a compiled ELF binary disguised as source code. The file contains obfuscated machine code with no clear vulnerability context, and the README is empty, offering no technical details or analysis.

Classification
Trojan 99%
Attack Type
Other
Complexity
Unknown
Reliability
Unknown
Target: unknown
No auth needed
mistral-large-3 · analyzed Jul 22, 2026 Full analysis →

References (5)

Core 5
Core References
Release Notes, Vendor Advisory x_refsource_misc
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.13
Exploit, Third Party Advisory x_refsource_misc
https://www.youtube.com/watch?v=d5f9xLK8Vhw
Third Party Advisory x_refsource_confirm
https://security.netapp.com/advisory/ntap-20211104-0002/
Mailing List, Third Party Advisory mailing-list x_refsource_mlist
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.html

Scores

CVSS v3 7.8
EPSS 0.0156
EPSS Percentile 72.9%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-787
Status published
Products (11)
debian/debian_linux 9.0
linux/linux_kernel 2.6.12 - 4.4.282
netapp/h300e_firmware
netapp/h300s_firmware
netapp/h410c_firmware
netapp/h410s_firmware
netapp/h500e_firmware
netapp/h500s_firmware
netapp/h700e_firmware
netapp/h700s_firmware
... and 1 more
Published Oct 05, 2021
Tracked Since Feb 18, 2026