CVE-2026-1678Public exploitNetwork attack vector

Unauthenticated memory corruption via stale DNS buffer bound

Published Mar 5, 2026 · Updated Mar 5, 2026

Out-of-bounds write in Zephyr RTOS 4.3 and earlier allows remote attackers to corrupt memory via a crafted DNS response. dns_unpack_name() snapshots net_buf tailroom once, reuses that stale bound as labels extend the buffer, and writes a final null byte without a fresh bounds check. The path requires CONFIG_DNS_RESOLVER; with assertions disabled by default, the overwrite can crash the device or corrupt attacker-influenced memory.

CVSS severity9.4
Critical
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Zephyr RTOS 4.3 and earlier allows remote attackers to corrupt memory via a crafted DNS response. dns_unpack_name() snapshots net_buf tailroom once, reuses that stale bound as labels extend the buffer, and writes a final null byte without a fresh bounds check. The path requires CONFIG_DNS_RESOLVER; with assertions disabled by default, the overwrite can crash the device or corrupt attacker-influenced memory.

The record

CVE
CVE-2026-1678
Published
Mar 5, 2026
Updated
Mar 5, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-787, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=* <=4.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=* <=4.3

Published CVSS scores

9.4Zephyr ProjectCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1210Exploitation of Remote Services

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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