How severe is CVE-2026-29004?

CVE-2026-29004 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2026-29004 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-29004?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-29004 have an EU (EUVD) identifier?

Yes. CVE-2026-29004 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27043.

When was CVE-2026-29004 published?

CVE-2026-29004 was published on 2026-05-04 and last updated on 2026-06-30.

CVE-2026-29004

CVE-2026-29004 is a high-severity vulnerability with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-122.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v4: 7.2
EPSS exploit prediction: 0% (30th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-27043
Weakness: CWE-122
Published: 2026-05-04
Last modified: 2026-06-30

Description

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.

Frequently asked questions

What is CVE-2026-29004?: 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.
How severe is CVE-2026-29004?: CVE-2026-29004 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2026-29004 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-29004?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-29004 have an EU (EUVD) identifier?: Yes. CVE-2026-29004 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27043.
When was CVE-2026-29004 published?: CVE-2026-29004 was published on 2026-05-04 and last updated on 2026-06-30.

References

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