CVE-2026-88833

Busybox: busybox: udhcpc integer underflow in dhcp packet length calculation causes denial of service

Published Oct 13, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

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).

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Redhat rhel Els
CPEs cpe:/o:redhat:rhel_els:6
Vendors & Products Redhat rhel Els
Type Values Removed Values Added
First Time appeared Busybox
Busybox busybox
Vendors & Products Busybox
Busybox busybox
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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 9, 2026, 1:06 PM
Reserved
Sep 10, 2026, 9:42 AM
Status
Awaiting Analysis
Published
Oct 13, 2026, 5:17 PM
Modified
Nov 9, 2026, 1:17 PM
Severity
Moderate
Public date
Oct 13, 2026, 1:49 PM