Client-side script execution via HTML-rendered error toast
Published Feb 20, 2026 · Updated Feb 20, 2026
Reflected XSS in LibreNMS before 26.2.0 allows remote attackers to execute script in another user’s browser through the email field. LibrenmsSetting.vue passes server-returned validation errors directly to toastr.error as HTML instead of assigning them as text. Exploitation requires another user to view the resulting toast; the script runs in that user’s browser and can access or alter session-visible data.
Summary
What happened
Reflected XSS in LibreNMS before 26.2.0 allows remote attackers to execute script in another user’s browser through the email field. LibrenmsSetting.vue passes server-returned validation errors directly to toastr.error as HTML instead of assigning them as text. Exploitation requires another user to view the resulting toast; the script runs in that user’s browser and can access or alter session-visible data.
The record
- CVE
- CVE-2026-26987
- Published
- Feb 20, 2026
- Updated
- Feb 20, 2026
- Vendor
- LibreNMS
- Product
- LibreNMS
- Classifications
- CWE-79, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 20, 2026CVE publishedPublication date reported by the CVE source.
- Feb 20, 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=< 26.2.0
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
- Email-field reflected XSS proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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