CVE-2026-53921

🚨 CVE-2026-53921 - odhcpd Critical Stack-Based Buffer Overflow in OpenWrt odhcpd A remote unauthenticated stack-based buffer overflow allowing potentialRemote Code Execution RCE with root privileges. 📖 Overview Property| Value ---|--- CVE ID| CVE-2026-53921 Severity| 🔴 Critical CVSS v3.1| 9.8 CWE...

CVE-2026-53921-PoC-Exploit

CVE-2026-53921 – odhcpd Stack Overflow For educational and authorized testing only. Unauthorized use is illegal. Vulnerability Overview CVE-2026-53921 is a critical stack buffer overflow in OpenWrt’s odhcpd daemon – the default DHCPv6/DHCPv4/RA server. How it works The vulnerability exists in...

CVE-2026-53920

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 IANA or IAPD option whose body is shorter than struct dhcpv6iahdr, casts the option header to that full structure, and reads ia-iaid...

CVE-2026-55606

odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In versions 25.12 and prior, odhcpd's DHCPv6 self-loop detection at dhcpv6.c:720 uses a network-byte-order DUID length value directly as the memcmp size parameter. On little-endian hosts, this causes memcmp to read far...

CVE-2026-53918

odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. Prior to version 25.12, odhcpd's DHCPv6 IA handler keeps a per-message first lease pointer so multiple IA options in one message reuse the same Reconfigure authentication key. A DHCPv6 REQUEST from an adjacent-network...

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...

CVE-2026-55606 odhcpd: Stack buffer overread via DUID length endianness mismatch in memcmp()

odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In versions 25.12 and prior, odhcpd's DHCPv6 self-loop detection at dhcpv6.c:720 uses a network-byte-order DUID length value directly as the memcmp size parameter. On little-endian hosts, this causes memcmp to read far...

CVE-2026-55606

The odhcpd server, used by OpenWrt in versions 25.12 and prior , is vulnerable to a stack buffer overread due to a DUID length endianness mismatch in dhcpv6.c:720. On little-endian hosts , the software uses a network-byte-order DUID length value directly as a memcmp() size parameter, allowing a s...

CVE-2026-53918

The odhcpd DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt is vulnerable to a heap-use-after-free (UAF) read in its DHCPv6 IA handler prior to version 25.12 . The issue occurs because the handler maintains a per-message first lease pointer; an adjacent-network client can craft a D...

CVE-2026-53918 odhcpd DHCPv6 IA dangling first pointer use-after-free

odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. Prior to version 25.12, odhcpd's DHCPv6 IA handler keeps a per-message first lease pointer so multiple IA options in one message reuse the same Reconfigure authentication key. A DHCPv6 REQUEST from an adjacent-network...

CVE-2026-53920

The odhcpd DHCPv6, DHCPv4, and router-advertisement server (used by OpenWrt ) is vulnerable to a stack disclosure in versions 17.01.0 through before 25.12.3 . The vulnerability exists because the DHCPv6 IA parser accepts IA_NA or IA_PD options with bodies shorter than the expected struct dhcpv6_i...

EUVD-2026-108968

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 IANA or IAPD option whose body is shorter than struct dhcpv6iahdr, casts the option header to that full structure, and reads ia-iaid...

CVE-2026-53920 odhcpd DHCPv6 Short IA_NA/IA_PD Body Stack Disclosure

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 IANA or IAPD option whose body is shorter than struct dhcpv6iahdr, casts the option header to that full structure, and reads ia-iaid...

CVE-2026-53920 odhcpd DHCPv6 Short IA_NA/IA_PD Body Stack Disclosure

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 IANA or IAPD option whose body is shorter than struct dhcpv6iahdr, casts the option header to that full structure, and reads ia-iaid...

CVE-2026-53921

A critical stack-based buffer overflow exists in the odhcpd daemon of OpenWrt , affecting versions prior to 24.10.8 and 25.12.5 . The vulnerability is triggered during the serialization of DHCPv6 Reply packets in the build_ia() and dhcpv6_ia_handle_IAs() functions. When processing a specially cra...

CVE-2026-53921 odhcpd: Stack buffer overflow in DHCPv6 IA reply serialization (2 independent sites)

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...

CVE-2026-53922

odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In commit cfddd56 and earlier, an unauthenticated host on the same link can first obtain two bindings through normal DHCPv6 SOLICIT and REQUEST exchanges and then send a crafted RENEW containing multiple IANA options. ...

CVE-2026-53922 odhcpd: pre-auth remote DoS via size_t underflow in dhcpv6_ia_handle_IAs (stack BOF, canary-terminated)

odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In commit cfddd56 and earlier, an unauthenticated host on the same link can first obtain two bindings through normal DHCPv6 SOLICIT and REQUEST exchanges and then send a crafted RENEW containing multiple IANA options. ...

CVE-2026-53922 odhcpd: pre-auth remote DoS via size_t underflow in dhcpv6_ia_handle_IAs (stack BOF, canary-terminated)

odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In commit cfddd56 and earlier, an unauthenticated host on the same link can first obtain two bindings through normal DHCPv6 SOLICIT and REQUEST exchanges and then send a crafted RENEW containing multiple IANA options. ...

CVE-2026-53922

The odhcpd DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt is vulnerable to a pre-auth remote Denial of Service (DoS) . In versions prior to commit cfddd56 , an unauthenticated host on the same link can trigger a size_t underflow within the dhcpv6_ia_handle_IAs function. By sendin...