BusyBox udhcpc DHCP Client Integer Underflow DoS
CVE-2026-88833 Published on October 13, 2026
Busybox: busybox: udhcpc integer underflow in dhcp packet length calculation causes denial of service
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.
Vulnerability Analysis
Timeline
Reported to Red Hat.
Made public. 34 days later.
Weakness Type
What is an Integer underflow Vulnerability?
The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result. This can happen in signed and unsigned cases.
CVE-2026-88833 has been classified to as an Integer underflow vulnerability or weakness.
Products Associated with CVE-2026-88833
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