CVE-2023-3040Network attack vector

Service interruption via debug parser out-of-bounds read

Published Jun 14, 2023 · Updated Jan 2, 2025

Out-of-bounds read in Cloudflare lua-resty-json allows attackers to interrupt a service when debug parsing handles untrusted JSON. The dump_obj debug function reads reverse_nesting_order unconditionally even when the parsed object is not composite, accessing outside the intended bounds. The path exists only in tests and demos, so standard deployments are not exploitable; a consumer must expose the debug parser to untrusted data for service interruption.

CVSS severity3.7
Low
EPSS probability0.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Cloudflare lua-resty-json allows attackers to interrupt a service when debug parsing handles untrusted JSON. The dump_obj debug function reads reverse_nesting_order unconditionally even when the parsed object is not composite, accessing outside the intended bounds. The path exists only in tests and demos, so standard deployments are not exploitable; a consumer must expose the debug parser to untrusted data for service interruption.

The record

CVE
CVE-2023-3040
Published
Jun 14, 2023
Updated
Jan 2, 2025
Vendor
Cloudflare
Product
lua-resty-json
Classifications
CWE-125, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 14, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 2, 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=1 <14 changes=[{"at":"14","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cloudflare · lua-resty-jsonversion=1 <14 changes=[{"at":"14","status":"unaffected"}]

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.7Cloudflare, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

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 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 exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

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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