Cross-site scripting via incomplete attribute value normalization
Published May 26, 2026 · Updated May 26, 2026
Cross-site scripting in Joomla Filter Package 1.0.0 through 3.0.5 and 4.0.0 through 4.0.1 allows attackers to inject script. The checkAttribute methods decoded and lowercased attribute values but failed to remove XSS-evasion whitespace and null bytes before applying the dangerous-protocol pattern, allowing crafted attributes to pass. High-privilege access is required to supply the content, and a victim must render an affected component; execution occurs in the victim's browser context.
Summary
What happened
Cross-site scripting in Joomla Filter Package 1.0.0 through 3.0.5 and 4.0.0 through 4.0.1 allows attackers to inject script. The checkAttribute methods decoded and lowercased attribute values but failed to remove XSS-evasion whitespace and null bytes before applying the dangerous-protocol pattern, allowing crafted attributes to pass. High-privilege access is required to supply the content, and a victim must render an affected component; execution occurs in the victim's browser context.
The record
- CVE
- CVE-2026-48903
- Published
- May 26, 2026
- Updated
- May 26, 2026
- Vendor
- Joomla! Project
- Product
- Joomla Filter Package
- Classifications
- CWE-79, CAPEC-18, T1203
- Attack vector
- network
- Privileges
- admin
Timeline
How it unfolded
- May 26, 2026CVE publishedPublication date reported by the CVE source.
- May 26, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1.0.0-3.0.5
- Affected versionversion=4.0.0-4.0.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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