Buffer overflow in Zephyrproject Zephyr
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 the buffer. With assertions disabled (default), a malicious DNS response can trigger an out-of-bounds write when CONFIG_DNS_RESOLVER is enabled.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.4 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (31.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 31.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000
Affected products
Weakness classification (CWE)
References
- github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-536f-h63g-hj42 (Exploit, Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-1678?
- CVE-2026-1678 is a critical-severity vulnerability in Zephyrproject Zephyr, classified under Out-of-bounds Write. CVSS score: 9.4/10. Published 2026-03-05.
- How severe is CVE-2026-1678?
- Critical severity. CVSS v3 base score is 9.4 out of 10.