CVE-2024-42058Network attack vector

Unauthenticated device crash via null pointer dereference

Published Sep 3, 2024 · Updated Sep 3, 2024

Null pointer dereference in Zyxel firewall firmware through 5.38 allows remote attackers to crash devices by sending crafted packets. Zyxel has not disclosed the packet-processing locus or the field whose dereference receives a null pointer. No authentication or user interaction is required, and exploitation interrupts firewall availability.

CVSS severity7.5
High
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Null pointer dereference in Zyxel firewall firmware through 5.38 allows remote attackers to crash devices by sending crafted packets. Zyxel has not disclosed the packet-processing locus or the field whose dereference receives a null pointer. No authentication or user interaction is required, and exploitation interrupts firewall availability.

The record

CVE
CVE-2024-42058
Published
Sep 3, 2024
Updated
Sep 3, 2024
Vendor
Zyxel Networks
Product
Zyxel USG FLEX 50W Firmware
Classifications
CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 3, 2024CVE publishedPublication date reported by the CVE source.
  2. Sep 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=5.20 <=5.38

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zyxel Networks · Zyxel USG FLEX 50W Firmwareversion=5.20 <=5.38
Zyxel Networks · USG20(W)-VPN Seriesversion=versions V5.20 through V5.38
Zyxel Networks · USG FLEX 50 Seriesversion=versions V5.20 through V5.38
Zyxel Networks · ZyWALL ATP800 Firmwareversion=4.32 <=5.38
Zyxel Networks · ATP Seriesversion=versions V4.32 through V5.38
Zyxel Networks · Zyxel USG FLEX 700H Firmwareversion=4.5 <=5.38
Zyxel Networks · USG FLEX Seriesversion=versions V4.50 through V5.38

Published CVSS scores

7.5Zyxel CorporationCVSS:3.1/AV:N/AC:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-476NULL Pointer Dereference
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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