CVE-2026-44990: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in apostrophecms sanitize-html
ApostropheCMS's sanitize-html package versions prior to 2.17.4 contain a cross-site scripting (XSS) vulnerability. The issue arises because attacker-controlled content inside a disallowed <xmp> element can be transformed into executable HTML or JavaScript under the default sanitizer configuration. This sanitizer bypass can lead to stored XSS when sanitized output is rendered back to users. Version 2.17.4 addresses this vulnerability.
AI Analysis
Technical Summary
The sanitize-html library used by ApostropheCMS versions before 2.17.4 has an improper input neutralization vulnerability (CWE-79). Specifically, under the default 'disallowedTagsMode: discard' setting, content inside disallowed <xmp> tags can be converted into live HTML or JavaScript, bypassing the sanitizer. This flaw enables stored cross-site scripting attacks in applications that render sanitized content to users. The vulnerability is tracked as CVE-2026-44990 with a CVSS 3.1 score of 9.3, indicating critical severity. The issue is fixed in version 2.17.4.
Potential Impact
Successful exploitation allows attackers to inject and execute arbitrary JavaScript in the context of users viewing sanitized content, leading to potential compromise of user sessions, data theft, or other malicious actions. The vulnerability affects confidentiality and integrity but does not impact availability. It is a critical security risk due to the high CVSS score and the nature of stored XSS.
Mitigation Recommendations
Upgrade sanitize-html to version 2.17.4 or later, where this vulnerability is fixed. No other mitigations are specified or recommended. Patch status is not explicitly stated in the vendor advisory, but the version 2.17.4 release is identified as the fix.
CVE-2026-44990: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in apostrophecms sanitize-html
Description
ApostropheCMS's sanitize-html package versions prior to 2.17.4 contain a cross-site scripting (XSS) vulnerability. The issue arises because attacker-controlled content inside a disallowed <xmp> element can be transformed into executable HTML or JavaScript under the default sanitizer configuration. This sanitizer bypass can lead to stored XSS when sanitized output is rendered back to users. Version 2.17.4 addresses this vulnerability.
CVSS v3.1
Score 9.3critical
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The sanitize-html library used by ApostropheCMS versions before 2.17.4 has an improper input neutralization vulnerability (CWE-79). Specifically, under the default 'disallowedTagsMode: discard' setting, content inside disallowed <xmp> tags can be converted into live HTML or JavaScript, bypassing the sanitizer. This flaw enables stored cross-site scripting attacks in applications that render sanitized content to users. The vulnerability is tracked as CVE-2026-44990 with a CVSS 3.1 score of 9.3, indicating critical severity. The issue is fixed in version 2.17.4.
Potential Impact
Successful exploitation allows attackers to inject and execute arbitrary JavaScript in the context of users viewing sanitized content, leading to potential compromise of user sessions, data theft, or other malicious actions. The vulnerability affects confidentiality and integrity but does not impact availability. It is a critical security risk due to the high CVSS score and the nature of stored XSS.
Mitigation Recommendations
Upgrade sanitize-html to version 2.17.4 or later, where this vulnerability is fixed. No other mitigations are specified or recommended. Patch status is not explicitly stated in the vendor advisory, but the version 2.17.4 release is identified as the fix.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-08T16:23:33.265Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a2c7589e617e2d834c30b62
Added to database: 6/12/2026, 9:09:29 PM
Last enriched: 6/12/2026, 9:24:47 PM
Last updated: 6/12/2026, 10:22:06 PM
Views: 3
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