CVE-2023-53978Public exploitNetwork attack vector

Stored XSS via unsanitized announcement titles

Published Dec 22, 2025 · Updated Dec 22, 2025

Stored XSS in MyBB 1.8.26 allows remote authenticated users with administrator access to execute JavaScript through announcement titles. The Forum Announcements Admin CP action stores the title parameter and renders it inside an HTML attribute without output encoding. Administrator access is required to create the announcement, and the payload executes in the browser of a user who views the affected forum.

CVSS severity5.1
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in MyBB 1.8.26 allows remote authenticated users with administrator access to execute JavaScript through announcement titles. The Forum Announcements Admin CP action stores the title parameter and renders it inside an HTML attribute without output encoding. Administrator access is required to create the announcement, and the payload executes in the browser of a user who views the affected forum.

The record

CVE
CVE-2023-53978
Published
Dec 22, 2025
Updated
Dec 22, 2025
Vendor
MyBB
Product
MyBB
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Dec 22, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 22, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=1.8.26

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

MyBB · MyBBversion=1.8.26

Published CVSS scores

5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
5.4VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

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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