CRITICALCVSS v3.1 9.8Vulnerability
CVE-2026-53921
odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. Prior to version 25.12, odhcpd's DHCPv6 IA response handler writes past the end of a fixed 512-byte stack buffer (pdbuf) when a single DHCPv6 REQUEST carries enough IA options to nearly exhaust the reply space. Two independent overflow sites exist in the same call chain, both reachable from the network via a single unauthenticated UDP packet. odhcpd runs as root on OpenWrt; embedded targets often lack stack canaries and ASLR, making code execution realistic. This issue has been patched in version 25.12.
Properties
- Severity
- CRITICAL
- Nvd fetched at
- 2026-10-23T14:24:59.572098+00:00
- Cvss severity
- CRITICAL
- Cvss score
- 9.8
- Retrieved at
- 2026-10-23T14:28:02+00:00
- Score
- 9.8
- Cvss version
- 3.1
- Last source
- NVD
- Cve id
- CVE-2026-53921
- Cvss vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- First seen by Signal
- 2026-10-23T14:28:02+00:00
- Name
- CVE-2026-53921
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published at
- 2026-10-23T14:17:53.710
- Last modified
- 2026-10-23T14:17:53.710
Related Entities (1)
HAS_WEAKNESS (1)
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