CVE-2023-4540Network attack vector

Service hang via premature content-length stream closure

Published Sep 5, 2023 · Updated Apr 4, 2025

Improper exception handling in Daurnimator lua-http before commit ddab283 allows remote attackers to hang servers via crafted HTTP requests. The HTTP/1 stream reader fails to treat premature EOF as an error when a content-length body ends early, so shutdown repeatedly drains a stream that cannot supply the declared bytes. An unauthenticated peer must close a length-delimited connection early; the affected server then remains in an infinite loop and loses availability.

CVSS severity7.5
High
EPSS probability1.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper exception handling in Daurnimator lua-http before commit ddab283 allows remote attackers to hang servers via crafted HTTP requests. The HTTP/1 stream reader fails to treat premature EOF as an error when a content-length body ends early, so shutdown repeatedly drains a stream that cannot supply the declared bytes. An unauthenticated peer must close a length-delimited connection early; the affected server then remains in an infinite loop and loses availability.

The record

CVE
CVE-2023-4540
Published
Sep 5, 2023
Updated
Apr 4, 2025
Vendor
Daurnimator
Product
lua-http
Classifications
CWE-755, CAPEC-130, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 5, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 4, 2025Record 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=0 <commit ddab283

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Daurnimator · lua-httpversion=0 <commit ddab283

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

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-755Improper Handling of Exceptional Conditions
CAPEC-130Excessive Allocation
T1499.004Endpoint Denial of Service: Application 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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo