# CVE-2026-56113: dhcpcd Heap Use-After-Free in dhcp6_deprecateaddrs via DHCPv6 RENEW

> Unauthenticated attackers can crash the dhcpcd daemon by sending crafted DHCPv6 RENEW replies, causing a heap use-after-free.

- **Severity:** Medium 6.0 (`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`)
- **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-2026-56113, AZL-90213, BELL-CVE-2026-56113, DEBIAN-CVE-2026-56113, GHSA-vh4p-87xg-jc4x, UBUNTU-CVE-2026-56113

## What is CVE-2026-56113?

CVE-2026-56113 is a medium-severity use after free 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 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.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-56113?

It affects 1 product.


Products: Dhcpcd Project Dhcpcd.

## How do I fix CVE-2026-56113?

Apply the vendor's patch.

## Is CVE-2026-56113 being exploited?

There is no known exploitation of CVE-2026-56113 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-2026-56116](https://insights.sbomify.com/CVE-2026-56116/): dhcpcd Memory Leak DoS via IPv6 Router Advertisement Handling (high 7.1)
- [CVE-2014-7912](https://insights.sbomify.com/CVE-2014-7912/): Memory corruption in n/a (medium 6.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56113 and fix it if it is affected.

What it is: CVE-2026-56113 is a medium-severity use after free 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-2026-56113 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-2026-56113/ (Markdown: https://insights.sbomify.com/CVE-2026-56113/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56113
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56113
- OSV: https://osv.dev/vulnerability/CVE-2026-56113

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-56113/
Summaries are generated and may contain mistakes; the official description above is the record.