CVE-2026-55790: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in craftcms cms
Craft CMS versions 4.0.0-RC1 through 4.17.15 and 5.0.0-RC1 through 5.9.22 contain a cross-site scripting (XSS) vulnerability. An attacker with only a GitHub account can inject JavaScript code into issue titles in the craftcms/cms GitHub repository. When a Craft admin uses the CraftSupport widget's "Give feedback" screen and searches for terms that return the malicious issue, the payload executes in the admin's control panel session without requiring any elevated privileges. The vulnerability is fixed in versions 4.17.16 and 5.9.23.
AI Analysis
Technical Summary
CVE-2026-55790 is a cross-site scripting (CWE-79) vulnerability in Craft CMS affecting versions 4.0.0-RC1 through 4.17.15 and 5.0.0-RC1 through 5.9.22. The issue arises because an attacker with only a GitHub account can plant a JavaScript payload in an issue title on the craftcms/cms GitHub repository. When a Craft CMS administrator uses the CraftSupport widget's "Give feedback" screen and performs a search that returns the poisoned issue, the malicious script executes within the admin's control panel session. This occurs without the attacker needing any control panel account or elevated privileges. The vulnerability is resolved in versions 4.17.16 and 5.9.23.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of the Craft CMS admin control panel session. This can lead to session hijacking, unauthorized actions, or other malicious activities within the admin interface. The attacker does not require any elevated privileges or control panel access, only a GitHub account. This elevates the risk as the attack vector is accessible to a wide range of users.
Mitigation Recommendations
A fix is available in Craft CMS versions 4.17.16 and 5.9.23. Users should upgrade to these or later versions to remediate this vulnerability. No other mitigation steps are indicated by the vendor advisory.
CVE-2026-55790: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in craftcms cms
Description
Craft CMS versions 4.0.0-RC1 through 4.17.15 and 5.0.0-RC1 through 5.9.22 contain a cross-site scripting (XSS) vulnerability. An attacker with only a GitHub account can inject JavaScript code into issue titles in the craftcms/cms GitHub repository. When a Craft admin uses the CraftSupport widget's "Give feedback" screen and searches for terms that return the malicious issue, the payload executes in the admin's control panel session without requiring any elevated privileges. The vulnerability is fixed in versions 4.17.16 and 5.9.23.
CVSS v4.0
Score 7.4high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-55790 is a cross-site scripting (CWE-79) vulnerability in Craft CMS affecting versions 4.0.0-RC1 through 4.17.15 and 5.0.0-RC1 through 5.9.22. The issue arises because an attacker with only a GitHub account can plant a JavaScript payload in an issue title on the craftcms/cms GitHub repository. When a Craft CMS administrator uses the CraftSupport widget's "Give feedback" screen and performs a search that returns the poisoned issue, the malicious script executes within the admin's control panel session. This occurs without the attacker needing any control panel account or elevated privileges. The vulnerability is resolved in versions 4.17.16 and 5.9.23.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of the Craft CMS admin control panel session. This can lead to session hijacking, unauthorized actions, or other malicious activities within the admin interface. The attacker does not require any elevated privileges or control panel access, only a GitHub account. This elevates the risk as the attack vector is accessible to a wide range of users.
Mitigation Recommendations
A fix is available in Craft CMS versions 4.17.16 and 5.9.23. Users should upgrade to these or later versions to remediate this vulnerability. No other mitigation steps are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-17T14:40:28.380Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a45a10627e9c79719523622
Added to database: 07/01/2026, 23:21:42 UTC
Last enriched: 07/01/2026, 23:36:23 UTC
Last updated: 07/01/2026, 23:36:23 UTC
Views: 4
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