CVE-2020-18731Public exploitNetwork attack vector

Unauthenticated server crash via malformed firmware-update frame

Published Aug 23, 2021 · Updated Aug 4, 2024

NULL pointer dereference in Iec104_Deal_FirmUpdate in IEC104 1.0 allows remote attackers to crash the server via a crafted firmware-update frame. The parser accepts a 43-byte firmware-update frame whose length field declares 208 bytes, then reaches a call through address zero inside the handler. No authentication or user interaction is required; processing the single malformed frame aborts the IEC104 server and interrupts its service.

CVSS severity7.5
High
EPSS probability1.41%
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 Iec104_Deal_FirmUpdate in IEC104 1.0 allows remote attackers to crash the server via a crafted firmware-update frame. The parser accepts a 43-byte firmware-update frame whose length field declares 208 bytes, then reaches a call through address zero inside the handler. No authentication or user interaction is required; processing the single malformed frame aborts the IEC104 server and interrupts its service.

The record

CVE
CVE-2020-18731
Published
Aug 23, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

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-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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