Administrator session theft via unsanitized iframe URL
Published Feb 15, 2021 · Updated Jul 9, 2026
Reflected XSS in Nagios XI 5.7.5 allows remote attackers to execute script in an administrator's browser through a crafted SSH Terminal URL. The sshterm.php page copies the unvalidated url parameter directly into an iframe src attribute, so a javascript scheme executes in the page context. Exploitation requires an administrator to follow the malicious URL; the resulting script can read session cookies, while command execution requires chaining with separate flaws.
Summary
What happened
Reflected XSS in Nagios XI 5.7.5 allows remote attackers to execute script in an administrator's browser through a crafted SSH Terminal URL. The sshterm.php page copies the unvalidated url parameter directly into an iframe src attribute, so a javascript scheme executes in the page context. Exploitation requires an administrator to follow the malicious URL; the resulting script can read session cookies, while command execution requires chaining with separate flaws.
The record
- CVE
- CVE-2021-25299
- Published
- Feb 15, 2021
- Updated
- Jul 9, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-79, T1189
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 15, 2021CVE publishedPublication date reported by the CVE source.
- Jul 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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
- Nagios XI 5.7.5 SSH Terminal XSS proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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