CVE-2026-18430
HumHub 1.18.4 - Stored XSS in comment-deletion notifications through unescaped administrator reason
Description
HumHub 1.18.4 contains a stored cross-site scripting vulnerability in the comment-deletion notification flow. A Space administrator can delete another user's comment, choose to notify the original author, and place HTML/JavaScript in the deletion reason.
INFO
Published Date :
Aug. 19, 2026, 4:17 p.m.
Last Modified :
Aug. 19, 2026, 4:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-18430
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | 84fe0718-d6bb-4716-a7e8-81a6d1daa869 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update HumHub to the latest version.
- Review application security settings.
- Sanitize user-generated content.
- Implement output encoding for all data.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-18430.
| URL | Resource |
|---|---|
| https://fluidattacks.com/es/advisories/personajes | |
| https://github.com/humhub/humhub | |
| https://github.com/humhub/humhub/pull/8365 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-18430 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-18430
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-18430 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-18430 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Aug. 19, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/humhub/humhub', 'vendor': 'HumHub', 'product': 'HumHub', 'versions': [{'status': 'affected', 'version': '1.18.4'}], 'platforms': ['Windows', 'MacOS', 'Linux'], 'defaultStatus': 'unaffected'}] Added Description HumHub 1.18.4 contains a stored cross-site scripting vulnerability in the comment-deletion notification flow. A Space administrator can delete another user's comment, choose to notify the original author, and place HTML/JavaScript in the deletion reason. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/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 Added CWE CWE-79 Added Reference https://fluidattacks.com/es/advisories/personajes Added Reference https://github.com/humhub/humhub Added Reference https://github.com/humhub/humhub/pull/8365