CVE-2022-43972

Adjacent-network UPnP crash via null dereference

Published Jan 9, 2023 · Updated Apr 9, 2025

Null pointer dereference in Linksys WRT54GL firmware 4.30.18.006 and earlier allows remote attackers to crash the UPnP service. The soap_action function in the upnp binary dereferences a null pointer while processing a crafted POST request that invokes AddPortMapping. The attacker needs adjacent-network access to the router; successful exploitation interrupts UPnP service without exposing or modifying data.

CVSS severity6.5
Medium
EPSS probability1.31%
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 Linksys WRT54GL firmware 4.30.18.006 and earlier allows remote attackers to crash the UPnP service. The soap_action function in the upnp binary dereferences a null pointer while processing a crafted POST request that invokes AddPortMapping. The attacker needs adjacent-network access to the router; successful exploitation interrupts UPnP service without exposing or modifying data.

The record

CVE
CVE-2022-43972
Published
Jan 9, 2023
Updated
Apr 9, 2025
Vendor
Linksys
Product
WRT54GL Wireless-G Broadband Router
Classifications
CWE-476, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 9, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 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=Firmware <=4.30.18.006

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Linksys · WRT54GL Wireless-G Broadband Routerversion=Firmware <=4.30.18.006

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.5Trellix CNACVSS:3.1/AV:A/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.

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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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

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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