CVE-2023-50784Network attack vector

Pre-authentication server crash via unchecked WebSocket copy

Published Dec 16, 2023 · Updated Nov 4, 2025

Buffer overflow in UnrealIRCd 6.1.0 through 6.1.3 allows remote attackers to crash the server via oversized WebSocket packets. During frame reassembly, one WebSocket parsing function checks packet length against a larger first buffer, but a second function uses memcpy to copy the data into a smaller static buffer without another bounds check. A nondefault WebSocket listen block must be enabled; exploitation is pre-authentication and normally causes a crash, while vendor testing found no effects beyond a crash.

CVSS severity7.5
High
EPSS probability1.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in UnrealIRCd 6.1.0 through 6.1.3 allows remote attackers to crash the server via oversized WebSocket packets. During frame reassembly, one WebSocket parsing function checks packet length against a larger first buffer, but a second function uses memcpy to copy the data into a smaller static buffer without another bounds check. A nondefault WebSocket listen block must be enabled; exploitation is pre-authentication and normally causes a crash, while vendor testing found no effects beyond a crash.

The record

CVE
CVE-2023-50784
Published
Dec 16, 2023
Updated
Nov 4, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 16, 2023CVE 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?

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

7.5UnrealIRCdCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.2UnrealIRCdCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:H/RL:O/RC:C

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
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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