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.
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History
Fri, 23 Oct 2026 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | odhcpd DHCPv6 Short IA_NA/IA_PD Body Stack Disclosure | |
| Weaknesses | CWE-125 CWE-126 CWE-200 CWE-201 |
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cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-10-23T13:20:48.045Z
Reserved: 2026-06-11T15:46:12.316Z
Link: CVE-2026-53920
No data.
Status : Received
Published: 2026-10-23T14:17:53.573
Modified: 2026-10-23T14:17:53.573
Link: CVE-2026-53920
No data.
OpenCVE Enrichment
Updated: 2026-10-23T16:30:18Z