VDB-244583 · CVE-2023-45556 · GHSA-4xqm-3cm2-5xgf

MyBB 1.8.33 Theme Management Theme Name cross site scripting

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.4	$0-$5k	0.00

Summaryinfo

A vulnerability has been found in MyBB 1.8.33 and classified as problematic. This impacts an unknown function of the component Theme Management. The manipulation of the argument Theme Name leads to cross site scripting. This vulnerability is listed as CVE-2023-45556. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in MyBB 1.8.33 (Content Management System). It has been rated as problematic. This issue affects an unknown part of the component Theme Management. The manipulation of the argument Theme Name with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. The summary by CVE is:

Cross Site Scripting vulnerability in Mybb Mybb Forums v.1.8.33 allows a local attacker to execute arbitrary code via the theme Name parameter in the theme management component.

The weakness was presented 11/07/2023 as GHSA-4xqm-3cm2-5xgf. It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2023-45556 since 10/09/2023. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/10/2026). The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2023-49848). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Content Management System

Name

MyBB

Version

1.8.33

License

open-source

Website

Product: https://mybb.com/

CPE 2.3info

🔍

CPE 2.2info

🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.4

VulDB Base Score: 3.5
VulDB Temp Score: 3.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.4
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Timelineinfo

10/09/2023 🔍
11/07/2023 +29 days 🔍
11/07/2023 +0 days 🔍
02/10/2026 +826 days 🔍

Sourcesinfo

Product: mybb.com

Advisory: GHSA-4xqm-3cm2-5xgf
Status: Confirmed

CVE: CVE-2023-45556 (🔍)
GCVE (CVE): GCVE-0-2023-45556
GCVE (VulDB): GCVE-100-244583
EUVD: 🔍

Entryinfo

Created: 11/07/2023 03:20
Updated: 02/10/2026 18:11
Changes: 11/07/2023 03:20 (40), 12/02/2023 16:45 (11), 02/10/2026 18:11 (16)
Complete: 🔍
Cache ID: 216::103