CVE-2026-56114

Service interruption via DHCPv6 stack buffer overwrite

Published Jun 23, 2026 · Updated Jun 23, 2026

Stack out-of-bounds write in dhcpcd 10.3.2 and earlier allows remote attackers to interrupt the service via DHCPv6. In dhcp6_makemessage(), serialization of an RFC 6603 prefix-exclusion body can place 17 bytes into a 16-byte stack buffer. The crafted ADVERTISE must arrive from the same IPv6 link while the client processes delegated-prefix data; the overwrite corrupts adjacent stack memory and interrupts dhcpcd.

CVSS severity6.0
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack out-of-bounds write in dhcpcd 10.3.2 and earlier allows remote attackers to interrupt the service via DHCPv6. In dhcp6_makemessage(), serialization of an RFC 6603 prefix-exclusion body can place 17 bytes into a 16-byte stack buffer. The crafted ADVERTISE must arrive from the same IPv6 link while the client processes delegated-prefix data; the overwrite corrupts adjacent stack memory and interrupts dhcpcd.

The record

CVE
CVE-2026-56114
Published
Jun 23, 2026
Updated
Jun 23, 2026
Vendor
Network Configuration
Product
dhcpcd
Classifications
CWE-787, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=10.3.2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Network Configuration · dhcpcdversion=0 <=10.3.2

Published CVSS scores

6.0VulnCheckCVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.3VulnCheckCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
6.5NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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