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CVE-2026-56113

dhcpcd Heap Use-After-Free in dhcp6_deprecateaddrs via DHCPv6 RENEW

No known exploitation. EPSS puts it in the 19th percentile. Fixed in 5733d3c59a5651f64357ac11c98b4f39895c8d25.

CVSS 3.15.3MediumEPSS percentile19th0.3% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix5733d3c59a5651f64357ac11c98b4f39895c8d25Upgrade to this build

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • NetworkConfiguration dhcpcdAffected: ≤ 10.3.2Upgrade to: after 10.3.2Fixed builds5733d3c59a5651f64357ac11c98b4f39895c8d25Stated by: CVE record
  • Dhcpcd Project DhcpcdAffected: ≤ 10.3.2Upgrade to: after 10.3.2Stated by: NVD

Versions as the sources state them. Full version matrix after sign-in

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

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.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS19th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.3% chance of exploitation activity in the next 30 days, which ranks it in the 19th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

10 events over 124 days, from the signal feeds we watch.

  1. Patch availablerecord updated
  2. OpenVAS check added
  3. Patch availablerecord updated
  4. Patch availablerecord updated
  5. Publishedweakness classified, att&ck mapped

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Scored 5.3 by NVD.

How it is reached

  • Attack Vector AdjacentRequires access to the local network (e.g. same Wi-Fi, Bluetooth)
  • Attack Complexity HighRequires specific conditions like a race condition or non-default configuration
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity NoneNo integrity impact
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

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