CVE-2026-1678
CVE-2026-1678 is a critical-severity vulnerability in Zephyrproject Zephyr with a CVSS 3.x base score of 9.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: Critical (CVSS 3.x base score 9.4)
- EPSS exploit prediction: 0% (30th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-9792
- Weakness: CWE-787
- Affected product: Zephyrproject Zephyr
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2026-1678?
- CVE-2026-1678 has a CVSS 3.x base score of 9.4, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability high.
- Is CVE-2026-1678 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-1678?
- CVE-2026-1678 affects Zephyrproject Zephyr. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-1678?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- Does CVE-2026-1678 have an EU (EUVD) identifier?
- Yes. CVE-2026-1678 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9792.
- When was CVE-2026-1678 published?
- CVE-2026-1678 was published on 2026-03-05 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*
More vulnerabilities in Zephyrproject Zephyr
- CVE-2026-5067 — Critical (CVSS 9.8): A remote, unauthenticated attacker can trigger memory corruption in Zephyr's HTTP server WebSocket upgrade path by…
- CVE-2022-3806 — Critical (CVSS 9.8): Inconsistent handling of error cases in bluetooth hci may lead to a double free condition of a network buffer.
- CVE-2017-14199 — Critical (CVSS 9.8): A buffer overflow has been found in the Zephyr Project's getaddrinfo() implementation in 1.9.0 and 1.10.0.
- CVE-2018-1000800 — Critical (CVSS 9.8): zephyr-rtos version 1.12.0 contains a NULL base pointer reference vulnerability in sys_ring_buf_put(),…
- CVE-2021-3329 — Critical (CVSS 9.6): Lack of proper validation in HCI Host stack initialization can cause a crash of the bluetooth stack
- CVE-2023-0397 — Critical (CVSS 9.6): A malicious / defect bluetooth controller can cause a Denial of Service due to unchecked input in…
All CVEs affecting Zephyrproject Zephyr →
Other CWE-787 (Out-of-bounds Write) vulnerabilities
- CVE-2026-42369 — Critical (CVSS 10.0): GV-VMS V20 is a Video Monitoring Software used to gather the feeds of many surveillance cameras and manage other…
- CVE-2026-4746 — Critical (CVSS 10.0): Out-of-bounds Write vulnerability in timeplus-io proton (base/poco/Foundation/src modules). This vulnerability is…
- CVE-2025-43300 — Critical (CVSS 10.0): An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 15.8.5 and iPadOS…
- CVE-2025-24201 — Critical (CVSS 10.0): An out-of-bounds write issue was addressed with improved checks to prevent unauthorized actions. This issue is fixed in…
- CVE-2024-42479 — Critical (CVSS 10.0): llama.cpp provides LLM inference in C/C++. The unsafe `data` pointer member in the `rpc_tensor` structure can cause…
- CVE-2024-39791 — Critical (CVSS 10.0): Stack-based buffer overflow vulnerabilities affecting Vonets industrial wifi bridge relays and wifi bridge…