CVE-2024-23336Network attack vector

Authenticated SSRF via incomplete loopback denylist

Published May 1, 2024 · Updated Aug 1, 2024

SSRF in MyBB before 1.8.38 allows remote authenticated users to make the server request loopback or internal IPv4 resources. The fetch_remote_file() denylist in inc/config.php blocks 127.0.0.1 but omits the rest of 127.0.0.0/8, so alternate loopback addresses pass validation. A low-privilege account and a reachable URL-fetching path are required; the result is limited to server-originated requests whose downstream effect depends on the targeted service.

CVSS severity5.0
Medium
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in MyBB before 1.8.38 allows remote authenticated users to make the server request loopback or internal IPv4 resources. The fetch_remote_file() denylist in inc/config.php blocks 127.0.0.1 but omits the rest of 127.0.0.0/8, so alternate loopback addresses pass validation. A low-privilege account and a reachable URL-fetching path are required; the result is limited to server-originated requests whose downstream effect depends on the targeted service.

The record

CVE
CVE-2024-23336
Published
May 1, 2024
Updated
Aug 1, 2024
Vendor
MyBB
Product
MyBB
Classifications
CWE-918, CWE-184, CAPEC-664, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

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

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.8.38
  2. Affected versionversion=< 1.8.38

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MyBB · MyBBversion=0 <1.8.38; version=< 1.8.38

Published CVSS scores

5.0GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
CWE-184Incomplete List of Disallowed Inputs
CAPEC-664Server Side Request Forgery
T1190Exploit Public-Facing Application

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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