PT-2026-51562 · Networkconfiguration · Dhcpcd

Cub3Y0Nd + 1 · Published 2026-06-23 · Updated 2026-06-23 · CVE-2026-56113

Mitre

CVSS v3.1

5.3

Medium

Base vector

AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

dhcpcd through 10.3.2, fixed in commit 5733d3c, contains a heap use-after-free vulnerability that allows unauthenticated same-link attackers to crash the daemon by sending a crafted DHCPv6 RENEW reply with RFC6603 OPTION PD EXCLUDE and both preferred and valid lifetimes set to zero. Attackers acting as or impersonating a DHCPv6 server can trigger dhcp6 deprecatedele() to free a delegated child address while an outer TAILQ FOREACH SAFE iterator in dhcp6 deprecateaddrs() still holds the freed pointer, causing a use-after-free when TAILQ REMOVE is reached.

Fix

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

CVE-2026-56113

Affected Products

Dhcpcd

References · 3

• https://github.com/NetworkConfiguration/dhcpcd/commit/5733d3c59a5651f64357ac11c98b4f39895c8d25 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-56113 · Security Note
• https://vulncheck.com/advisories/dhcpcd-heap-use-after-free-in-dhcp6-deprecateaddrs-via-dhcpv6-renew · Note