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Fencer Vulns
medium 6.5

CVE-2026-56116 json

dhcpcd Memory Leak DoS via IPv6 Router Advertisement Handling

published 2026-06-23 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-38496

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

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.

Patch / fix

  • dhcpcd_project dhcpcd 10.5.0
  • dhcpcd Debian 13 1:10.1.0-11+deb13u3
  • dhcpcd Debian 14 1:10.3.2-4

debian advisories DEBIAN-CVE-2026-56116

  • dhcpcd SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 10.5.0-160000.1.1

suse advisories SUSE-SU-2026:23400-1SUSE-SU-2026:23562-1

  • dhcpcd openSUSE Leap 16.0 10.5.0-160000.1.1
  • dhcpcd openSUSE Tumbleweed 10.5.0-1.1

opensuse advisories openSUSE-SU-2026:21692-1openSUSE-SU-2026:11473-1

  • dhcpcd Alpine 3.24, Alpine 3.23 10.5.2-r0

alpine advisories ALPINE-CVE-2026-56116

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • dhcpcd Azure Linux 3.0 10.0.8-2

azure linux advisories AZL-90219

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-56116 updated cvss 6.5

dhcpcd: dhcpcd: Denial of Service via IPv6 Router Advertisement memory leak

  • Red Hat Enterprise Linux 10 dhcpcd
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 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
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • NetworkConfiguration dhcpcd

Classification

Weakness
  • CWE-401 Missing Release of Memory after Effective Lifetime

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.