CVE-2026-56113CWE-416

dhcpcd Heap Use-After-Free in dhcp6_deprecateaddrs via DHCPv6 RENEW

Medium · published June 23, 2026

CVSS v4.0
6.0
EPSS
0%
Percentile
18.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.0 · MEDIUM
Vector
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
EPSS
0.00269 · 18.0th percentile
Weakness
CWE-416 · Use After Free
Published
2026-06-23T16:05Z
EPSS history
Timeline
  • 23 JUN 16:05Z
    dhcpcd Heap Use-After-Free in dhcp6_deprecateaddrs via DHCPv6 RENEW
    cvelistv5