CVE-2026-56116: dhcpcd through 10.3.2, fixed in commit 708b4a5, contains a memory leak vulnerability in the IPv6 Router Advert

Routine

MEDIUM 6.5UPGRADE

CVE-2026-56116 is a medium-severity flaw (CVSS 6.5) affecting dhcpcd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 linea

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Weakness	CWE-401
Published	2026-06-23
Last modified	2026-10-25

Publisher (CNA): VulnCheck · Vendor: dhcpcd project

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-23 17:17 UTCPublished CVE record published
2026-10-25 23:10 UTCUpdated Record last modified

dhcpcd project dhcpcd UPGRADE

Affected: >= 10.0.7 and < 10.5.0

Fixed in: 10.5.0

Safe to downgrade to: a release before 10.0.7

1. Check installed version

apt-cache policy dhcpcd || rpm -q dhcpcd || dhcpcd --version

2. UPGRADE to 10.5.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade dhcpcd

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade dhcpcd

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 10.0.7 (Debian / Ubuntu)

apt-cache madison dhcpcd sudo apt install dhcpcd=<VERSION_BEFORE_10.0.7> sudo apt-mark hold dhcpcd

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list dhcpcd sudo dnf downgrade dhcpcd-<VERSION_BEFORE_10.0.7> sudo dnf versionlock add dhcpcd

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-56116?

dhcpcd: upgrade to 10.5.0. Exact commands for each OS are on this page.

Is CVE-2026-56116 being exploited?

CVE-2026-56116 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-56116 affect?

CVE-2026-56116 affects dhcpcd. Severity is medium (CVSS 6.5). 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

How urgent is CVE-2026-56116?

Priority 28/100. No elevated risk signals yet.

Related CVEs

CVE-2026-56113 MEDIUM 5.3 UPGRADE dhcpcd through 10.3.2, fixed in commit 5733d3c, contains a heap use-after-free vulnerability that allows unaut
CVE-2026-56114 MEDIUM 5.3 UPGRADE dhcpcd through 10.3.2, fixed in commit 2f00c7b, contains a one-byte stack out-of-bounds write vulnerability in
CVE-2026-56117 MEDIUM 4.7 UPGRADE dhcpcd through 10.3.2, fixed in commit 78ea09e, contains a heap use-after-free vulnerability in the control so

References

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