Cyber Resilience

CVE-2024-23336

SSRF in Mybb ≤ 1.8.38

Published
01 May 2024
Modified
30 June 2025
Patch / advisory
CVSS Score v3.1 5.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
EPSS Score 0.0046 38th percentile
Risk Priority 40 floored blend · peak EPSS

Summary

CVE-2024-23336 is a medium-severity Incomplete List of Disallowed Inputs (CWE-184) vulnerability in Mybb Mybb. Its CVSS base score is 5.0 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 38th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

MyBB is a free and open source forum software. The default list of disallowed remote hosts does not contain the `127.0.0.0/8` block, which may result in a Server-Side Request Forgery (SSRF) vulnerability. The Configuration File's _Disallowed Remote Addresses_ list (`$config['disallowed_remote_addresses']`)…

more

contains the address `127.0.0.1`, but does not include the complete block `127.0.0.0/8`. MyBB 1.8.38 resolves this issue in default installations. Administrators of installed boards should update the existing configuration (`inc/config.php`) to include all addresses blocked by default. Additionally, users are advised to verify that it includes any other IPv4 addresses resolving to the server and other internal resources. Users unable to upgrade may manually add 127.0.0.0/8' to their disallowed address list.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-29457Same product: Mybb Mybb
CVE-2025-29460Same product: Mybb Mybb
CVE-2025-29459Same product: Mybb Mybb
CVE-2025-29458Same product: Mybb Mybb
CVE-2023-53979Same product: Mybb Mybb
CVE-2025-48940Same product: Mybb Mybb
CVE-2024-52702Same product: Mybb Mybb
CVE-2023-45556Same product: Mybb Mybb
CVE-2024-23335Same product: Mybb Mybb
CVE-2023-53976Same product: Mybb Mybb

Affected Assets

mybb
mybb
≤ 1.8.38

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)
  • V3.5.2
  • V4.4.2
  • V16.2.5
  • V1.3.6

Mitigating Controls (NIST 800-53 r5) AI

Information flow enforcement can restrict which destinations the server is allowed to contact on behalf of users.

SI-10 requires validity checks on inputs, which structurally replaces incomplete deny-lists with complete allow-list or sanitization logic.

Boundary protection limits the network reach of server-initiated requests even if SSRF occurs.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require complete, positive input validation instead of incomplete denylists.

DE.CM-09 partial match
prevents

Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover and record SSRF flaws in web applications.

PR.IR-01 partial match
prevents

Network segmentation and egress controls can limit the damage from successful SSRF requests.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can discover missing input checks, but does not prevent the weakness during development.

prevents

Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.

prevents

Application security requirements can mandate complete input validation rules, but the control itself does not prescribe how to build those rules.

prevents

Secure architecture principles include robust input validation design, yet the control is broader than this single weakness.

prevents

Secure coding standards directly require exhaustive allow-lists or complete deny-lists for inputs, addressing the root cause of incomplete disallowed-input lists.

References