Is there a public PoC exploit available for CVE-2018-25309?

Yes, a public proof-of-concept exploit is available for CVE-2018-25309. Prioritise patching immediately. EPSS: 0.0%.

Mybb Recent Threads CVE-2018-25309

Q: What is the CVSS score of CVE-2018-25309?

CVE-2018-25309 has a CVSS 4.0 base score of 5.1 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

EUVD-2018-21830 MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2026-04-29 VulnCheck

XSS Mybb Recent Threads

5.1

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

5.1 MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Scope

Lifecycle Timeline

PoC Detected

May 01, 2026 - 19:15 vuln.today

Public exploit code

Severity Changed

Apr 29, 2026 - 20:22 NVD

HIGH MEDIUM

CVSS changed

Apr 29, 2026 - 20:22 NVD

7.2 (HIGH) 5.1 (MEDIUM)

EUVD ID Assigned

Apr 29, 2026 - 20:00 euvd

EUVD-2018-21830

CVE Published

Apr 29, 2026 - 19:24 nvd

MEDIUM 5.1

DescriptionCVE.org

MyBB Recent threads 17.0 contains a persistent cross-site scripting vulnerability that allows attackers to inject malicious scripts by creating threads with crafted subject lines. Attackers can create threads with script tags in the subject parameter to execute arbitrary JavaScript in the browsers of all users viewing the index page.

AnalysisAI

MyBB Recent threads 17.0 contains a persistent cross-site scripting vulnerability that allows attackers to inject malicious scripts by creating threads with crafted subject lines. Rated medium severity (CVSS 5.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. MyBB Recent threads 17.0 contains a persistent cross-site scripting vulnerability that allows attackers to inject malicious scripts by creating threads with crafted subject lines. Attackers can create threads with script tags in the subject parameter to execute arbitrary JavaScript in the browsers of all users viewing the index page. Affected products include: Mybb Mybb Recent Threads.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.