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NVD / CVE Program· CNA VulnCheck

CVE-2026-56114: dhcpcd Stack Out-of-Bounds Write in dhcp6_makemessage()

MediumCVSS 6.0 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 24/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.26% (FIRST EPSS).
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: dhcpcd (Alpine:v3.23) 10.5.2-r0; dhcpcd5 (Debian:12) 9.4.1-24~deb12u5; dhcpcd (Debian:13) 1:10.1.0-11+deb13u3.

Low priority for now. Upgrade to dhcpcd (Alpine:v3.23) 10.5.2-r0; dhcpcd5 (Debian:12) 9.4.1-24~deb12u5; dhcpcd (Debian:13) 1:10.1.0-11+deb13u3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Jun 23, 2026
Updated
Oct 25, 2026
EPSS
0.2% · 19th percentile

Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
24 / 40 · 6.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · VulnCheck
6.0
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
dhcpcd projectdhcpcd

Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.

  • NetworkConfiguration dhcpcd

    • 2f00c7bfc408b6582d331932dfa47829c4819029not affected
    • up to and including 10.3.2affected · semver

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • dhcpcd project dhcpcdup to 10.3.2 inclusive

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.23dhcpcdbefore 10.5.2-r010.5.2-r0
Debian:12dhcpcd5before 9.4.1-24~deb12u59.4.1-24~deb12u5
Debian:13dhcpcdbefore 1:10.1.0-11+deb13u31:10.1.0-11+deb13u3
Debian:14dhcpcdbefore 1:10.3.2-41:10.3.2-4

Same product

dhcpcd project: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-11577dhcpcd before 7.2.1 contains a buffer overflow in dhcp6_findna in dhcp6.c when reading NA/TA addresses.
    55Plan
  • CVE-2016-1503dhcpcd before 6.10.0, as used in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-04-01 and other…
    41Plan
  • CVE-2019-11766dhcp6.c in dhcpcd before 6.11.7 and 7.x before 7.2.2 has a buffer over-read in the D6_OPTION_PD_EXCLUDE feature.
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2019-11579Apr 28, 2019 · dhcp.c in dhcpcd before 7.2.1 contains a 1-byte read overflow with DHO_OPTSOVERLOADED.
    21Monitor
  • ← EarlierCVE-2026-56113Jun 23, 2026 · dhcpcd Heap Use-After-Free in dhcp6_deprecateaddrs via DHCPv6 RENEW
    24Monitor
  • Later →CVE-2026-56116Jun 23, 2026 · dhcpcd Memory Leak DoS via IPv6 Router Advertisement Handling
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:dhcpcd10.5.2-r0 · Alpine:v3.23Package registry (OSV)
debian:dhcpcd1:10.1.0-11+deb13u3 · Debian:13Package registry (OSV)
debian:dhcpcd59.4.1-24~deb12u5 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Not on record for this CVE: EPSS history · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

CVSS:4.0/AV:A/AC:L/AT:P/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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records