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CRITICAL · 9.4

CVE-2026-1678

dns_unpack_name() caches the buffer tailroom once and reuses it while appending DNS labels. As the buffer grows, the cached size becomes incorrect, and the final null terminator can be written past th...

Vulnerability Description

dns_unpack_name() caches the buffer tailroom once and reuses it while appending DNS labels. As the buffer grows, the cached size becomes incorrect, and the final null terminator can be written past the buffer. With assertions disabled (default), a malicious DNS response can trigger an out-of-bounds write when CONFIG_DNS_RESOLVER is enabled.

CVSS Score

9.4

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
HIGH

Affected Products

VendorProductVersions
ZephyrprojectZephyr<= 4.3.0

Related Weaknesses (CWE)

CWE-787

References

FAQ

What is CVE-2026-1678?

CVE-2026-1678 is a vulnerability with a CVSS score of 9.4 (CRITICAL). dns_unpack_name() caches the buffer tailroom once and reuses it while appending DNS labels. As the buffer grows, the cached size becomes incorrect, and the final null terminator can be written past th...

How severe is CVE-2026-1678?

CVE-2026-1678 has been rated CRITICAL with a CVSS base score of 9.4/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-1678?

Check the references section above for vendor advisories and patch information. Affected products include: Zephyrproject Zephyr.