XSS in Unclecode Crawl4ai
CVE-2026-91944
crawl4ai versions before 0.9.3 contain a DOM-based cross-site scripting vulnerability in the Playground UI where the forceHighlightElement() function assigns textContent back to innerHTML, re-parsing JSON responses as HTML. Attackers can inject malicious scripts through crawled page content like the page title to steal the operator's API token from sessionStorage and gain full server control.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (18.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 18.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/unclecode/crawl4ai/security/advisories/GHSA-m446-hp3q-qfxp (vendor-advisory)
- www.vulncheck.com/advisories/crawl4ai-before-0.9.3-dom-based-xss-via-playground… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-91944?
- CVE-2026-91944 is a medium-severity vulnerability in Unclecode Crawl4ai, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-09-15.
- How severe is CVE-2026-91944?
- Medium severity. CVSS v3 base score is 6.1 out of 10.