Vulnerability · Published Dec 2, 2025 · Assigned by GitHub_M

CVE-2025-66458Lookyloo has multiple XSS due to unsafe use of f-strings in Markup

Medium 5.3

In plain English

A medium-severity cross-site scripting in lookyloo from Lookyloo. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities).

Severity (CVSS 4.0)5.3Medium

Exploit odds (30 days)0.2%top 89.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
Lookyloo	lookyloo	< 1.35.3

Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

References

https://github.com/Lookyloo/lookyloo/security/advisories/GHSA-58h2-652v-gq87 x_refsource_CONFIRM
https://github.com/Lookyloo/lookyloo/commit/b6ee2fee0afff0b35f37dd891bbce9d53ed8a290 x_refsource_MISC