---
id: CVE-2026-53920
title: odhcpd DHCPv6 Short IA_NA/IA_PD Body Stack Disclosure
summary: >-
  odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt.
  From version 17.01.0 to before version 25.12.3, odhcpd's DHCPv6 IA parser
  accepts an IA_NA or IA_PD option whose body is shorter than struct
  dhcpv6_ia_hdr, ca…
severity: high
cvss: 8.7
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-125
  - CWE-126
  - CWE-200
  - CWE-201
vendor: openwrt
product: odhcpd
affected:
  - 'odhcpd >= 17.01.0, < 25.12.3'
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-23T17:33:12.791918Z'
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T20:58:10.536Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-53920'
references:
  - url: 'https://github.com/openwrt/odhcpd/security/advisories/GHSA-p769-5v73-pc4f'
    label: 'https://github.com/openwrt/odhcpd/security/advisories/GHSA-p769-5v73-pc4f'
  - url: >-
      https://github.com/openwrt/odhcpd/commit/719fc3abc0d7e7059871f9f572fb05ada86b8ff2
    label: >-
      https://github.com/openwrt/odhcpd/commit/719fc3abc0d7e7059871f9f572fb05ada86b8ff2
  - url: >-
      https://github.com/openwrt/odhcpd/commit/f2275efc72a87a95f971f159babcbadc5d241d42
    label: >-
      https://github.com/openwrt/odhcpd/commit/f2275efc72a87a95f971f159babcbadc5d241d42
tags:
  - cve.org
ingestedAt: '2026-10-23T14:28:08.713Z'
---

## Overview

odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. From version 17.01.0 to before version 25.12.3, odhcpd's DHCPv6 IA parser accepts an IA_NA or IA_PD option whose body is shorter than struct dhcpv6_ia_hdr, casts the option header to that full structure, and reads ia->iaid before proving that the IA body contains the IAID field. If an unauthenticated network-adjacent client places a zero-length or otherwise short IA option at the end of odhcpd's 8192-byte receive stack buffer, the IAID read crosses from data_buf into adjacent stack memory. The disclosed bytes are then reflected in the DHCPv6 reply IAID; prior ARM validation showed data_buf[8192:8196] disclosing the saved stack canary, and wider stack scans can leak ASLR-useful stack/process contents. This issue has been patched in version 25.12.3.

## Affected

- `odhcpd >= 17.01.0, < 25.12.3`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.