CVE-2026-91944: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in unclecode crawl4ai
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.
AI Analysis
Technical Summary
CVE-2026-91944 is a DOM-based cross-site scripting vulnerability in unclecode's crawl4ai product affecting versions prior to 0.9.3. The issue exists in the Playground UI where the forceHighlightElement() function improperly assigns textContent to innerHTML, causing JSON responses to be interpreted as HTML. This flaw enables attackers to inject malicious scripts through content from crawled pages, such as the page title. Successful exploitation can result in theft of sensitive session data like API tokens and may allow attackers to gain full control over the server.
Potential Impact
An attacker exploiting this vulnerability can inject malicious scripts that steal the operator's API token from sessionStorage. This token theft can lead to unauthorized access and full control over the crawl4ai server, compromising confidentiality and integrity of the system.
Mitigation Recommendations
A fix is available in crawl4ai version 0.9.3 and later. Users should upgrade to version 0.9.3 or newer to remediate this vulnerability. No vendor advisory was provided, so patch status is based on the version information given.
CVE-2026-91944: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in unclecode crawl4ai
Description
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.
CVSS v4.0
Score 5.1medium
Affected software
unclecode
crawl4ai
pkg:github/unclecode/crawl4aiRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-91944 is a DOM-based cross-site scripting vulnerability in unclecode's crawl4ai product affecting versions prior to 0.9.3. The issue exists in the Playground UI where the forceHighlightElement() function improperly assigns textContent to innerHTML, causing JSON responses to be interpreted as HTML. This flaw enables attackers to inject malicious scripts through content from crawled pages, such as the page title. Successful exploitation can result in theft of sensitive session data like API tokens and may allow attackers to gain full control over the server.
Potential Impact
An attacker exploiting this vulnerability can inject malicious scripts that steal the operator's API token from sessionStorage. This token theft can lead to unauthorized access and full control over the crawl4ai server, compromising confidentiality and integrity of the system.
Mitigation Recommendations
A fix is available in crawl4ai version 0.9.3 and later. Users should upgrade to version 0.9.3 or newer to remediate this vulnerability. No vendor advisory was provided, so patch status is based on the version information given.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-09-15T11:07:01.913Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6aa9651a55bf5e2cf502eb09
Added to database: 09/15/2026, 15:32:42 UTC
Last enriched: 09/15/2026, 15:48:03 UTC
Last updated: 09/16/2026, 02:32:18 UTC
Views: 9
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