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Vulnerability record · CVE-2026-1678 · published 5 March 2026

CVE-2026-1678: Zephyrproject zephyr out-of-bounds write vulnerability

Zephyrproject · Zephyr

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.

9.8 CVSS 3.1 Critical EPSS 0.38% · top 71.1% CWE-787 · Out-of-bounds write
9.8CVSS 3.1 base score
0.38%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

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

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2023-4260Zephyrproject zephyr classic buffer overflow vulnerabilityPotential off-by-one buffer overflow vulnerability in the Zephyr fuse file system.EPSS 0.77%9.8CVE-2026-10666Zephyrproject zephyr stack-based buffer overflow vulnerabilityparse_ipv4() in subsys/net/ip/utils.c (reached via net_ipaddr_parse() for strings of the form "a.b.c.d:port") copies the port substring into a fixed …EPSS 0.65%9.8CVE-2026-5067Zephyrproject zephyr out-of-bounds write vulnerabilityA remote, unauthenticated attacker can trigger memory corruption in Zephyr's HTTP server WebSocket upgrade path by sending a crafted Sec-WebSocket-Ke…EPSS 0.87%9.8CVE-2023-6881Zephyrproject zephyr classic buffer overflow vulnerabilityPossible buffer overflow in is_mount_pointEPSS 0.44%9.8CVE-2023-6249Zephyrproject zephyr vulnerabilitySigned to unsigned conversion esp32_ipm_sendEPSS 0.44%9.8CVE-2023-5779Zephyrproject zephyr out-of-bounds write vulnerabilitycan: out of bounds in remove_rx_filter functionEPSS 0.44%9.8CVE-2023-6749Zephyrproject zephyr stack-based buffer overflow vulnerabilityUnchecked length coming from user input in settings shellEPSS 0.44%9.8CVE-2023-5055Zephyrproject zephyr stack-based buffer overflow vulnerabilityPossible variant of CVE-2021-3434 in function le_ecred_reconf_req.EPSS 0.75%

Source: NIST National Vulnerability Database (record CVE-2026-1678), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.