Lookyloo has multiple XSS due to unsafe use of f-strings in Markup
Priority LOW 23CWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- None · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.
Summary
Lookyloo is a web interface that allows users to capture a website page and then display a tree of domains that call each other. Prior to 1.35.3, there are multiple XSS due to unsafe use of f-strings in Markup. The issue requires a malicious 3rd party server responding with a JSON document containing JS code in a script element. This vulnerability is fixed in 1.35.3.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00202 10th percentileScored 2026-11-07
Fix Fixed lookyloo (Lookyloo): 1.35.3
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA lookyloo (Lookyloo) Fixed in 1.35.3
Timeline
- 2026-10-02 Threatist record created from CVE-2025-66458
References
More Lookyloo vulnerabilities
- TI-2025-40891 Lookyloo vulnerable to XSS due to unescaped error message passed to innerHTML CVSS 4.0MEDIUM 5.3
- TI-2025-40892 Lookyloo vulnerable to XSS due to lack of escaping in HTML elements passed to Datatables CVSS 4.0MEDIUM 5.3
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences