# CVE-2026-56115 — NetworkConfiguration dhcpcd

> As of 2026-06-25, CVE-2026-56115 is a MEDIUM-severity vulnerability in NetworkConfiguration dhcpcd, CVSS v3.1 5.3, EPSS 0.1% (7.1th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-56115 as of 2026-06-25; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-06-25

## What is CVE-2026-56115?

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.

The record classifies CVE-2026-56115 under weakness class [CWE-787](https://intel.threadlinqs.com/cwe/CWE-787). Its CVSS v3 base vector states that the flaw is reachable from an adjacent network, needs no prior authentication, needs no user interaction, and has high impact on availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 104 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 5.3 — MEDIUM (`CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **CVSS v4.0 base score:** 6 (`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`)
- **EPSS (FIRST):** 0.1% probability of exploitation in the next 30 days, higher than 7.1% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 2.9/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-06-23, last modified 2026-06-25

## Is CVE-2026-56115 being exploited?

It currently carries a trending score of 31 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [NetworkConfiguration](https://intel.threadlinqs.com/vendors/networkconfiguration): dhcpcd

## How to fix CVE-2026-56115

No vendor patch reference has been recorded for CVE-2026-56115 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-56115

No threat campaign in the Threadlinqs corpus currently references CVE-2026-56115, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-06-25. This product uses the NVD API but is not endorsed or certified by the NVD.

**Exploit and proof of concept**

- [github.com — technical description](https://github.com/garybowers/bootimus/issues/84)

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/bootimus-broken-access-control-via-jwtmiddleware-authorization-bypass)

**Other references**

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

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-56115
Full detection coverage and IOCs for threats exploiting CVE-2026-56115 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp