Reflected XSS via HTML error response
Published Aug 4, 2026 · Updated Aug 4, 2026
Reflected XSS in Snowstorm before 10.12.2 allows remote attackers to execute JavaScript when a target follows a crafted link. WebRouteController.issueRedirect returns an invalid uri exception as raw text, while an attacker-controlled Accept header causes Spring to serve the response as text/html. Exploitation requires no authentication but requires a target user to open the link; script execution occurs in that user's browser context.
Summary
What happened
Reflected XSS in Snowstorm before 10.12.2 allows remote attackers to execute JavaScript when a target follows a crafted link. WebRouteController.issueRedirect returns an invalid uri exception as raw text, while an attacker-controlled Accept header causes Spring to serve the response as text/html. Exploitation requires no authentication but requires a target user to open the link; script execution occurs in that user's browser context.
The record
- CVE
- CVE-2026-66300
- Published
- Aug 4, 2026
- Updated
- Aug 4, 2026
- Vendor
- SNOMED International
- Product
- Snowstorm
- Classifications
- CWE-79, T1204.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 4, 2026CVE publishedPublication date reported by the CVE source.
- Aug 4, 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=7.0.0 <10.12.2
What conditions does exploitation require?
What is affected?
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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