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CVE-2026-56114

dhcpcd Stack Out-of-Bounds Write in dhcp6_makemessage()

Published: Jun 23, 2026Updated: Jul 14, 2026 Sources: CVE List NVDCWE-787
5.3MEDIUM
NVD MITRE
EPSS Score
0.2%
Top 92.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

Description

dhcpcd through 10.3.2, fixed in commit 2f00c7b, contains a one-byte stack out-of-bounds write vulnerability in dhcp6_makemessage() in src/dhcp6.c that allows unauthenticated same-link attackers to write beyond a fixed local buffer by serializing an oversized RFC6603 OPTION_PD_EXCLUDE option body. Attackers can send a crafted DHCPv6 ADVERTISE message containing an IA_PD IAPREFIX /0 with a valid OPTION_PD_EXCLUDE using an exclude prefix length of /121 through /128 to trigger the out-of-bounds write and potentially corrupt adjacent stack memory.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:AAC:HPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:AAttack Vector
Adjacent
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-787

Affected Products

NetworkConfiguration
oss-project
dhcpcdLibrary
Networking Infrastructure / dns-dhcp-ntp
dhcpcd project
oss-projectaka dhcpcd
dhcpcdOn-prem
Networking Infrastructure / dns-dhcp-ntp

Exploitability

Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Initial Access
Privilege Escalation
View detailed technique mapping

References

https://github.com/NetworkConfiguration/dhcpcd/commit/2f00c7bfc408b6582d331932dfa47829c4819029
github.com
https://www.vulncheck.com/advisories/dhcpcd-stack-out-of-bounds-write-in-dhcp6-makemessage
vulncheck.com

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