BusyBox udhcpc6 DHCPv6 client useafterfree DoS/Info Leak
CVE-2026-124740 Published on November 11, 2026
Busybox: use-after-free of requested_ipv6 in udhcpc6
A flaw was found in BusyBox's udhcpc6 DHCPv6 client. A malicious server on the local network can trigger a use-after-free condition by responding with a crafted Dynamic Host Configuration Protocol for IPv6 (DHCPv6) reply packet lacking usable address options. This issue causes the client to read stale heap memory, which can result in a Denial of Service (DoS) due to an application crash or disclose previously assigned network address data in subsequent discovery requests.
Vulnerability Analysis
Timeline
Reported to Red Hat.
Made public. 17 days later.
Weakness Type
What is a Dangling pointer Vulnerability?
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
CVE-2026-124740 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-124740
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