CVE-2026-56113
dhcpcd Heap Use-After-Free in dhcp6_deprecateaddrs via DHCPv6 RENEW
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.
INFO
Published Date :
June 23, 2026, 5:17 p.m.
Last Modified :
July 14, 2026, 10:17 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Apply the patch from commit 5733d3c to dhcpcd.
- Update dhcpcd to version 10.3.3 or later.
- Recompile and deploy the updated dhcpcd.
- Restart the dhcpcd service after updating.
Public PoC/Exploit Available at Github
CVE-2026-56113 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-56113.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-56113 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-56113
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-56113 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-56113 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://github.com/NetworkConfiguration/dhcpcd', 'vendor': 'NetworkConfiguration', 'product': 'dhcpcd', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '10.3.2'}, {'status': 'unaffected', 'version': '5733d3c59a5651f64357ac11c98b4f39895c8d25', 'versionType': 'git'}], 'defaultStatus': 'affected'}] [{'repo': 'https://github.com/NetworkConfiguration/dhcpcd', 'vendor': 'NetworkConfiguration', 'product': 'dhcpcd', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '10.3.2'}, {'status': 'unaffected', 'version': '5733d3c59a5651f64357ac11c98b4f39895c8d25', 'versionType': 'git'}], 'packageURL': 'pkg:github/NetworkConfiguration/dhcpcd', 'defaultStatus': 'affected'}] -
Initial Analysis by [email protected]
Jun. 28, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:dhcpcd_project:dhcpcd:*:*:*:*:*:*:*:* versions up to (including) 10.3.2 Added Reference Type VulnCheck: https://github.com/NetworkConfiguration/dhcpcd/commit/5733d3c59a5651f64357ac11c98b4f39895c8d25 Types: Patch Added Reference Type VulnCheck: https://www.vulncheck.com/advisories/dhcpcd-heap-use-after-free-in-dhcp6-deprecateaddrs-via-dhcpv6-renew Types: Third Party Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 23, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-56113', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-23T17:58:06.379364Z'} -
New CVE Received by [email protected]
Jun. 23, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/NetworkConfiguration/dhcpcd', 'vendor': 'NetworkConfiguration', 'product': 'dhcpcd', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '10.3.2'}, {'status': 'unaffected', 'version': '5733d3c59a5651f64357ac11c98b4f39895c8d25', 'versionType': 'git'}], 'defaultStatus': 'affected'}] Added 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. Added CVSS V4.0 AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-416 Added Reference https://github.com/NetworkConfiguration/dhcpcd/commit/5733d3c59a5651f64357ac11c98b4f39895c8d25 Added Reference https://www.vulncheck.com/advisories/dhcpcd-heap-use-after-free-in-dhcp6-deprecateaddrs-via-dhcpv6-renew