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Fencer Vulns
high 8.8

CVE-2026-29004 json

BusyBox DHCPv6 Client Heap Buffer Overflow via DNS_SERVERS

published 2026-05-04 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-27043

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

BusyBox before commit 42202bf contains a heap buffer overflow vulnerability in the DHCPv6 client (udhcpc6) DNS_SERVERS option handler in networking/udhcp/d6_dhcpc.c that allows network-adjacent attackers to trigger memory corruption by sending a crafted DHCPv6 response with a malformed D6_OPT_DNS_SERVERS option. Attackers can exploit incorrect heap buffer allocation calculations in the option_to_env() function to cause denial of service or achieve arbitrary code execution on embedded systems without heap hardening.

Patch / fix

  • Red Hat Red Hat Hardened Images 1.37.0-7.3.hum1
  • busybox hummingbird 1 1.37.0-7.3.hum1
  • busybox-shared hummingbird 1 1.37.0-7.3.hum1
  • busybox-petitboot hummingbird 1 1.37.0-7.3.hum1

red hat advisories RHSA-2026:30652

  • busybox SLES for SAP applications 16.0, SLES 16.0 1.37.0-160000.6.1

suse advisories SUSE-SU-2026:22020-1

  • busybox openSUSE Tumbleweed 1.37.0-11.1

opensuse advisories openSUSE-SU-2026:10740-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-29004 updated cvss 8.8

BusyBox: BusyBox: Arbitrary Code Execution via DHCPv6 Client Heap Buffer Overflow

  • Red Hat Hardened Images busybox 1.37.0-7.3.hum1, busybox-shared 1.37.0-7.3.hum1, busybox-petitboot 1.37.0-7.3.hum1
    fixed: vendor fix RHSA-2026:30652
  • Red Hat Enterprise Linux 6 busybox, busybox-petitboot
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • y637f9qq2x.com https://y637f9qq2x.com/posts/busybox-dhcpv6-heap-overflow/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 7.2 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
CNA 3.1 8.1 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CISA ADP 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 4.0 7.2 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • vda-linux busybox_mirror
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat Enterprise Linux 6

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow
  • CWE-131 Incorrect Calculation of Buffer Size

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.