CVE-2023-46566Public exploitNetwork attack vector

Unauthenticated server crash via undersized UDP datagram

Published Apr 29, 2024 · Updated Aug 2, 2024

Improper packet validation in tftpy allows remote attackers to crash a network-facing TFTP server with a short UDP datagram. TftpPacketFactory.parse passes the first two bytes to struct.unpack without ensuring that the received buffer contains a complete opcode, so a one-byte packet raises an uncaught struct.error. Any exposed tftpy UDP listener can be interrupted without authentication, while confidentiality and integrity remain unaffected.

CVSS severity7.5
High
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper packet validation in tftpy allows remote attackers to crash a network-facing TFTP server with a short UDP datagram. TftpPacketFactory.parse passes the first two bytes to struct.unpack without ensuring that the received buffer contains a complete opcode, so a one-byte packet raises an uncaught struct.error. Any exposed tftpy UDP listener can be interrupted without authentication, while confidentiality and integrity remain unaffected.

The record

CVE
CVE-2023-46566
Published
Apr 29, 2024
Updated
Aug 2, 2024
Vendor
Michael P. Soulier
Product
tftpy
Classifications
CWE-120, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 29, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 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?

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  1. Affected versionversion=-

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Michael P. Soulier · tftpyversion=-

Published CVSS scores

7.5CISA-ADPCVSS: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

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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-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Application 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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