dhcpcd Heap Use-After-Free in dhcp6_deprecateaddrs via DHCPv6 RENEW
Key facts
- Attack vector
- Adjacent network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| NetworkConfiguration | dhcpcd | up to 10.3.2 | — | Patch available | CNA |
- dhcpcd VendorNetworkConfiguration Affected up to 10.3.2 Fixed in — Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:dhcpcd_project:dhcpcd:*:*:*:*:*:*:*:* | up to 10.3.2 | Vulnerable | NetworkConfiguration |
- cpe:2.3:a:dhcpcd_project:dhcpcd:*:*:*:*:*:*:*:* Versions up to 10.3.2 Vulnerable ·NetworkConfiguration
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-56113
- 2026-10-03 Alias added: GHSA-vh4p-87xg-jc4x
References
More NetworkConfiguration Dhcpcd vulnerabilities
- TI-2019-08650 dhcpcd before 7.2.1 contains a buffer overflow in dhcp6_findna in dhcp6.c when reading NA/TA addresses. CVSS 3.0CRITICAL 9.8
- TI-2016-01390 dhcpcd before 6.10.0, as used in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x… CVSS 3.0CRITICAL 9.8
- TI-2019-08823 dhcp6.c in dhcpcd before 6.11.7 and 7.x before 7.2.2 has a buffer over-read in the D6_OPTION_PD_EXCLUDE feature. CVSS 3.1CRITICAL 9.8
- TI-2016-01391 dhcpcd before 6.10.0 allows remote attackers to cause a denial of service (invalid read… CVSS 3.0HIGH 7.5
- TI-2012-05402 The decode_search function in dhcp.c in dhcpcd 3.x does not properly free allocated… CVSS 3.0HIGH 7.5
- TI-2012-05401 The decode_search function in dhcp.c in dhcpcd 3.x allows remote DHCP servers to cause a… CVSS 3.0HIGH 7.5
Sources
- CVE-2026-56113 · CVE Program
- CVE-2026-56113 · NVD
- FIRST EPSS
- GHSA-vh4p-87xg-jc4x · GitHub Advisory Database · CC BY 4.0
- CVE-2026-56113 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences