A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.

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Advisories

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Fixes

Solution

No solution given by the vendor.


Workaround

If feasible, use udhcpc in LISTEN_KERNEL mode instead of LISTEN_RAW, or use an alternative DHCP client (dhclient, systemd-networkd). Restrict DHCP traffic on the local segment (for example DHCP snooping on switches).

History

Tue, 13 Oct 2026 19:15:00 +0000

Type Values Removed Values Added
First Time appeared Busybox
Busybox busybox
Vendors & Products Busybox
Busybox busybox

Tue, 13 Oct 2026 17:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.
Title Busybox: busybox: udhcpc integer underflow in dhcp packet length calculation causes denial of service
First Time appeared Redhat
Redhat hummingbird
Weaknesses CWE-191
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-10-13T16:56:11.068Z

Reserved: 2026-09-10T09:42:04.559Z

Link: CVE-2026-88833

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-13T17:17:48.007

Modified: 2026-10-13T17:17:48.007

Link: CVE-2026-88833

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-13T20:15:14Z

Weaknesses