Vulnerability Description
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.
Related Weaknesses (CWE)
References
- https://github.com/openwrt/odhcpd/commit/719fc3abc0d7e7059871f9f572fb05ada86b8ff
- https://github.com/openwrt/odhcpd/commit/f2275efc72a87a95f971f159babcbadc5d241d4
- https://github.com/openwrt/odhcpd/security/advisories/GHSA-p769-5v73-pc4f
FAQ
What is CVE-2026-53920?
CVE-2026-53920 is a documented vulnerability. 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 ...
How severe is CVE-2026-53920?
CVSS scoring is not yet available for CVE-2026-53920. Check NVD for updates.
Is there a patch for CVE-2026-53920?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.