CVE-2023-39540Public exploitNetwork attack vector

Remote crash via uninitialized ICMP buffer index

Published Feb 20, 2024 · Updated Nov 4, 2025

Buffer over-read in Gecko Platform 4.3.1.0 and uC-TCP-IP 3.06.01 allows remote attackers to crash devices with malformed IPv4 ICMP packets. The IPv4 receive path calls NetICMPv4_TxMsgErr before ICMP_MsgIx is initialized, and NetICMPv4_TxMsgErrValidate adds its 0xffff sentinel to DataPtr and dereferences the invalid pointer. Unauthenticated network reachability is sufficient, but malformed IPv4-header handling must reach ICMP error generation; the demonstrated consequence is a process crash.

CVSS severity5.9
Medium
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer over-read in Gecko Platform 4.3.1.0 and uC-TCP-IP 3.06.01 allows remote attackers to crash devices with malformed IPv4 ICMP packets. The IPv4 receive path calls NetICMPv4_TxMsgErr before ICMP_MsgIx is initialized, and NetICMPv4_TxMsgErrValidate adds its 0xffff sentinel to DataPtr and dereferences the invalid pointer. Unauthenticated network reachability is sufficient, but malformed IPv4-header handling must reach ICMP error generation; the demonstrated consequence is a process crash.

The record

CVE
CVE-2023-39540
Published
Feb 20, 2024
Updated
Nov 4, 2025
Vendor
Sigma Designs
Product
Gecko Platform
Classifications
CWE-125, CWE-126, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 20, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 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=4.3.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Sigma Designs · Gecko Platformversion=4.3.1.0
Weston Embedded Solutions · uC-TCP-IPversion=v3.06.01

Published CVSS scores

5.9Cisco TalosCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/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-125Out-of-bounds Read
CWE-126Buffer Over-read
T1499Endpoint Denial of Service

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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