CVE-2026-53920
SSVC: noneodhcpd DHCPv6 Short IA_NA/IA_PD Body Stack Disclosure
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CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Attack conditions and impact
Derived from the CNA (via NVD) CVSS 4.0 vectorThis vulnerability may be exploitable over the internet without authentication or user interaction.
| Metric | Value | Meaning |
|---|---|---|
| Attack vector AV | N | Network |
| Attack complexity AC | L | Low (easy) |
| Attack requirements AT | N | None |
| Privileges required PR | N | None |
| User interaction UI | N | None |
| Confidentiality (vulnerable system) VC | H | High |
| Integrity (vulnerable system) VI | N | None |
| Availability (vulnerable system) VA | N | None |
| Confidentiality (subsequent systems) SC | N | None |
| Integrity (subsequent systems) SI | N | None |
| Availability (subsequent systems) SA | N | None |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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.
CVSS assessments
| Provider | Version | Score | Vector |
|---|---|---|---|
| NVD / [email protected] (Secondary) | 4.0 | 8.7 HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| CNA / GitHub_M | 4.0 | 8.7 HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N |
Affected products and packages
CNA (CVE.org)
| Vendor | Product | Versions |
|---|---|---|
| openwrt | odhcpd | affected: >= 17.01.0, < 25.12.3 |
Linux distribution status
References (3)
- https://github.com/openwrt/odhcpd/commit/719fc3abc0d7e7059871f9f572fb05ada86b8ff2 NVD, CNA x_refsource_MISC
- https://github.com/openwrt/odhcpd/commit/f2275efc72a87a95f971f159babcbadc5d241d42 NVD, CNA x_refsource_MISC
- https://github.com/openwrt/odhcpd/security/advisories/GHSA-p769-5v73-pc4f NVD, CNA x_refsource_CONFIRM