# CVE-2026-56116: dhcpcd Memory Leak DoS via IPv6 Router Advertisement Handling

> An unauthenticated attacker can cause a denial of service in dhcpcd by sending crafted IPv6 Router Advertisements that trigger a memory leak.

- **Severity:** High 7.1 (`CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Jun 2026
- **Updated:** 28 Jul 2026
- **Also known as:** ALPINE-CVE-2026-56116, AZL-90219, BELL-CVE-2026-56116, DEBIAN-CVE-2026-56116, GHSA-g36w-q35r-qvg3, UBUNTU-CVE-2026-56116

## What is CVE-2026-56116?

CVE-2026-56116 is a high-severity denial of service vulnerability in NetworkConfiguration dhcpcd, published on 23 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

dhcpcd through 10.3.2, fixed in commit 708b4a5, contains a memory leak vulnerability in the IPv6 Router Advertisement route information handling that allows an unauthenticated same-link attacker to cause denial of service by sending crafted Router Advertisements. Attackers can repeatedly send Router Advertisements containing Route Information options with a lifetime of zero, triggering unfreed allocations in routeinfo_findalloc() that cause linear memory exhaustion and eventual daemon crash.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2026-56116?

It affects 1 product.


Products: Dhcpcd Project Dhcpcd.

## How do I fix CVE-2026-56116?

Apply the vendor's patch.

## Is CVE-2026-56116 being exploited?

There is no known exploitation of CVE-2026-56116 in the wild and no public exploit code.

## Other vulnerabilities in NetworkConfiguration dhcpcd

- [CVE-2019-11577](https://insights.sbomify.com/CVE-2019-11577/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-1503](https://insights.sbomify.com/CVE-2016-1503/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-1504](https://insights.sbomify.com/CVE-2016-1504/): dhcpcd before 6.10.0 allows remote attackers to cause a denial of service (invalid read and crash) via vectors related to the option length. (high 7.5)
- [CVE-2014-7912](https://insights.sbomify.com/CVE-2014-7912/): Memory corruption in n/a (medium 6.8)
- [CVE-2014-7913](https://insights.sbomify.com/CVE-2014-7913/): Memory corruption in n/a (medium 6.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56116 and fix it if it is affected.

What it is: CVE-2026-56116 is a high-severity denial of service vulnerability in NetworkConfiguration dhcpcd, published on 23 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-56116 in the wild and no public exploit code.

Affected product: NetworkConfiguration dhcpcd. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-56116/ (Markdown: https://insights.sbomify.com/CVE-2026-56116/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56116
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56116
- OSV: https://osv.dev/vulnerability/CVE-2026-56116

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-56116/
Summaries are generated and may contain mistakes; the official description above is the record.