CVE-2026-1678

dns: memory‑safety issue in the DNS name parser

Published Mar 5, 2026 CVSS 3.1 · 9.4 Critical EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Zephyrproject
Zephyrproject zephyr
CPEs cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*
Vendors & Products Zephyrproject
Zephyrproject zephyr
Type Values Removed Values Added
First Time appeared Zephyrproject-rtos
Zephyrproject-rtos zephyr
Vendors & Products Zephyrproject-rtos
Zephyrproject-rtos zephyr
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title dns: memory‑safety issue in the DNS name parser
Weaknesses CWE-787
References
Metrics cvssV3_1

{'score': 9.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
zephyr
Published
Updated
Oct 15, 2026, 10:10 PM
Reserved
Jan 30, 2026, 5:48 AM
Status
Analyzed
Published
Mar 5, 2026, 7:16 AM
Modified
Nov 5, 2026, 7:31 PM