CVE-2025-12899Public exploitNetwork attack vector

Memory disclosure via cross-family ICMP handler confusion

Published Jan 30, 2026 · Updated Jan 30, 2026

Type confusion in Zephyr RTOS 4.2 and earlier allows remote attackers to read out-of-bounds memory via a crafted IPv4 ICMP packet. A shared ICMP handler list matches IPv4 type 128 to icmpv6_handle_echo_request, which reinterprets the shorter IPv4 header as IPv6. The packet requires no authentication or user interaction; published testing demonstrates the invalid read but not extraction of significant memory in a reply.

CVSS severity6.5
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in Zephyr RTOS 4.2 and earlier allows remote attackers to read out-of-bounds memory via a crafted IPv4 ICMP packet. A shared ICMP handler list matches IPv4 type 128 to icmpv6_handle_echo_request, which reinterprets the shorter IPv4 header as IPv6. The packet requires no authentication or user interaction; published testing demonstrates the invalid read but not extraction of significant memory in a reply.

The record

CVE
CVE-2025-12899
Published
Jan 30, 2026
Updated
Jan 30, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-843
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 30, 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=* <=4.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=* <=4.2

Published CVSS scores

6.5Zephyr ProjectCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

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-843Access of Resource Using Incompatible Type ('Type Confusion')

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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