CVE-2026-56113
dhcpcd Heap Use-After-Free in dhcp6_deprecateaddrs via DHCPv6 RENEW
- State
- Published
- Severity
- 6.0 Medium
- Published
- Jun 23, 2026
- Updated
- Jul 28, 2026
- Reserved
- Jun 18, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.0 Medium | 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 | VulnCheck |
| 3.1 | 5.3 Medium | CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | VulnCheck |
Weaknesses
- CWE-416 Use After Free
Affected Products
| Product | Versions |
|---|---|
dhcpcdNetworkConfiguration |
|
References
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