CVE-2026-53920

8.7 HIGH 0.4% exploit odds Fix listed Memory safety Network gear

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-11 15:46 UTC ReservedThe CVE id was reserved by its CNA
2026-10-23 14:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-23 21:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 8.7 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-10-23 14:17 UTC
Last modified: 2026-10-23 21:17 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-125 · Out-of-bounds read
Record status: Deferred

Attack profile CVSS 4.0 · 8.7

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: None
User interaction: None
Confidentiality: High
Integrity: None
Availability: None

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-53920.md and follow it. Check whether this project is affected by CVE-2026-53920. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record