Joomla! Project Joomla CMS Extension up to 5.4.8/6.1.3 HTML Mail Templates HTML injection

CVSS Meta Temp Score
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Current Exploit Price (≈)
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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.
3.5$5k-$25k0.89-

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Joomla! Project Joomla CMS Extension up to 5.4.8/6.1.3. Affected by this issue is some unknown functionality of the component HTML Mail Templates. Performing a manipulation results in HTML injection. This vulnerability is cataloged as CVE-2026-90918. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability classified as problematic has been found in Joomla! Project Joomla CMS Extension up to 5.4.8/6.1.3. This affects an unknown functionality of the component HTML Mail Templates. The manipulation with an unknown input leads to a html injection vulnerability. CWE is classifying the issue as 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. This is going to have an impact on integrity. The summary by CVE is:

Joomla! Core - [20260908] - Core - XSS in HTML Mail Templates in Joomla 4.0.0-5.4.8, 6.0.0-6.1.3 - The mail template feature lacks an escaping mechanism, causing XSS vectors in multiple extensions.

This vulnerability is uniquely identified as CVE-2026-90918 since 09/14/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 09/29/2026). MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

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

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 3.5
VulDB Meta Temp Score: 3.5

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

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: HTML injection
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

09/14/2026 CVE reserved
09/29/2026 +15 days Advisory disclosed
09/29/2026 +0 days VulDB entry created
09/29/2026 +0 days VulDB entry last update

Sourcesinfo

Status: Confirmed

CVE: CVE-2026-90918 (🔒)
GCVE (CVE): GCVE-0-2026-90918
GCVE (VulDB): GCVE-100-411489

Entryinfo

Created: 09/29/2026 19:07
Changes: 09/29/2026 19:07 (64)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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