CVE-2025-1673Network attack vector

Device crash via unchecked DNS parsing error

Published Feb 25, 2025 · Updated Feb 28, 2025

Out-of-bounds reads in Zephyr RTOS 4.0 and earlier allow remote attackers to crash devices or corrupt DNS-related computation. The dns_validate_msg function accepts a 12-byte DNS message with ID 0 and QDCOUNT 1 after dns_unpack_response_query returns an error, then passes an out-of-bounds query_name pointer to crc16_ansi and strlen. A crafted packet needs no authentication or user interaction; memory-protected devices crash, while devices without memory protection can compute incorrect values.

CVSS severity8.2
High
EPSS probability0.34%
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 reads in Zephyr RTOS 4.0 and earlier allow remote attackers to crash devices or corrupt DNS-related computation. The dns_validate_msg function accepts a 12-byte DNS message with ID 0 and QDCOUNT 1 after dns_unpack_response_query returns an error, then passes an out-of-bounds query_name pointer to crc16_ansi and strlen. A crafted packet needs no authentication or user interaction; memory-protected devices crash, while devices without memory protection can compute incorrect values.

The record

CVE
CVE-2025-1673
Published
Feb 25, 2025
Updated
Feb 28, 2025
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-125, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 25, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 28, 2025Record 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=* <=4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=* <=4.0

Published CVSS scores

8.2Zephyr ProjectCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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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