CVE-2026-53921
odhcpd: Stack buffer overflow in DHCPv6 IA reply serialization (2 independent sites)
- Published
- Oct 23, 2026
- Updated
- Oct 23, 2026
- Assigning CNA
- GitHub_M
- Evidence observed
- Aug 4, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HLow · next 30 days
- Percentile
- 66.0%
- Model date
- Oct 25, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
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.
Sources
CVE-2026-53921
- CVE-2026-53921-PoC-ExploitExploit
CVE-2026-53921 – odhcpd Stack Overflow (CVSS 9.8) 🛡️ Vuln detailed and comprehensive Write-Up and Verifier & Multi-exploit for OpenWrt DHCPv6 RCE. Dual-vector (IA_NA/IA_PD) overflow with MIPS/ARM shellcode, ROP chains, SOCKS5 proxy, persistence, log wiping & mass scanning. Use Ethically, Stay Legal. 🔒
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