CVE-2026-1678 - Vulnerability Analysis

Overview

A DNS resolver with CONFIG_DNS_RESOLVER enabled contains a buffer overflow caused by incorrect buffer tailroom caching in dns_unpack_name(), letting attackers trigger out-of-bounds write via malicious DNS response, exploit requires crafted DNS response.

Severity & Score

Impact

Attackers can cause out-of-bounds write, potentially leading to memory corruption or denial of service.

Mitigation

Update to the latest version with the fix for buffer tailroom caching issue.

References

• https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-536f-h63g-hj42

Social Media Activity(1 post)

Patrick Mevzek

@pmevzek

Apr 1, 2026

@drewtowler @mdreid "Proof": https://www.0xkato.xyz/CVE-2026-1678-DNS-Parser-Overflow-in-Zephyr/ "critical out-of-bounds write in Zephyr’s DNS name parser, dns_unpack_name()". My lemmas remain that 1) any given software dealing with DNS will have a bug related to parsing and 2) any given software dealing with text will have a bug related to Unicode complexity. Works. All. The. Time.

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