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CVE-2023-46251· NVD / CVE Program· CNA GitHub_M

Visual editor persistent Cross-site Scripting (XSS) in MyBB

MyBB is a free and open source forum software. Custom MyCode (BBCode) for the visual editor (_SCEditor_) doesn't escape input properly when rendering HTML, resulting in a DOM-based XSS vulnerability. This weakness can be exploited by pointing a victim to a page where the visual editor is active (e.g. as a post or Private Message) and operates on a maliciously crafted MyCode message. This may occur on pages where message content is pre-filled using a GET/POST parameter, or on reply pages where a previously saved malicious message is quoted. The impact is be mitigated when: 1. the visual editor is disabled globally (_Admin CP → Configuration → Settings → Clickable Smilies and BB Code: [Clickable MyCode Editor](https://github.com/mybb/mybb/blob/mybb_1836/install/resources/settings.xml#L2087-L2094)_ is set to _Off_), or 2. the visual editor is disabled for individual user accounts (_User CP → Your Profile → Edit Options_: _Show the MyCode formatting options on the posting pages_ checkbox is not checked). MyBB 1.8.37 resolves this issue with the commit `6dcaf0b4d`. Users are advised to upgrade. Users unable to upgrade may mitigate the impact without upgrading MyBB by changing the following setting (_Admin CP → Configuration → Settings_): - _Clickable Smilies and BB Code → [Clickable MyCode Editor](https://github.com/mybb/mybb/blob/mybb_1836/install/resources/settings.xml#L2087-L2094)_: _Off_. Similarly, individual MyBB forum users are able to disable the visual editor by diabling the account option (_User CP → Your Profile → Edit Options_) _Show the MyCode formatting options on the posting pages_.

MediumCVSS 6.1 · v3.1—No exploit No fix recorded
Published
Nov 6, 2023
Updated
Jun 17, 2026
EPSS
0.5% · 39th percentile
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Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
24 / 40 · 6.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.1
CNA · GitHub_M
7.5
1.4 point gap

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Affected systems

VendorProduct
mybbmybb

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • mybb mybbbefore 1.8.37

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • mybb mybb

    • < 1.8.37affected

Same product

mybb: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-24734Remote code execution in mybb
    51Plan
  • CVE-2018-17128A Persistent XSS issue was discovered in the Visual Editor in MyBB before 1.8.19 via a Video MyCode.
    43Plan
  • CVE-2011-10018myBB 1.6.4 Backdoor Arbitrary Command Execution
    41Plan
  • CVE-2017-16780The installer in MyBB before 1.8.13 allows remote attackers to execute arbitrary code by writing to the configuration file.
    41Plan
  • CVE-2011-5133Unspecified vulnerability in MyBB before 1.6.5 has unknown impact and attack vectors, related to an "unparsed user avatar in the buddy list.
    41Plan
  • CVE-2015-2786Unspecified vulnerability in MyBB (aka MyBulletinBoard) before 1.8.4 has unknown attack vectors related to "Group join request notifications
    40Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2023-28467168 days apartIn MyBB before 1.8.34, there is XSS in the User CP module via the user email field.
    24Monitor
  • CVE-2022-43707350 days apartMyBB 1.8.31 has a Cross-site scripting (XSS) vulnerability in the visual MyCode editor (SCEditor) allows remote attackers to inject HTML via
    24Monitor
  • CVE-2022-43708350 days apartMyBB 1.8.31 has a (issue 2 of 2) cross-site scripting (XSS) vulnerabilities in the post Attachments interface allow attackers to inject HTML
    24Monitor
  • CVE-2023-455560 days apartCross Site Scripting vulnerability in Mybb Mybb Forums v.1.8.33 allows a local attacker to execute arbitrary code via the theme Name paramet
    21Monitor
  • CVE-2024-52702380 days apartA stored cross-site scripting (XSS) vulnerability in the component install\index.php of MyBB v1.8.38 allows attackers to execute arbitrary w
    21Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

nvd-primary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records