Vulnerability · Published Jul 15, 2026 · Assigned by GitHub_M

CVE-2026-52843Lightpanda: fetch() and XMLHttpRequest attach session cookies to cross-origin requests regardless of credentials mode

Critical 9.3

In plain English

A critical-severity security flaw in browser from lightpanda-io. 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 14% of all known vulnerabilities).

Severity (CVSS 3.1)9.3Critical

Exploit odds (30 days)0.2%top 85.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Lightpanda is a headless browser designed for AI and automation. Prior to 0.2.9, Lightpanda fetch() and XMLHttpRequest unconditionally attached session cookies to every HTTP request, ignoring credentials: omit, credentials: same-origin, credentials: include, and XMLHttpRequest.withCredentials, allowing an attacker-controlled origin in a Lightpanda session to issue authenticated cross-origin requests against a victim origin. This issue is fixed in version 0.2.9.

Affected products (as reported)

Vendor	Product	Versions
lightpanda-io	browser	< 0.2.9

Weakness: CWE-346 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

References

https://github.com/lightpanda-io/browser/security/advisories/GHSA-36mm-v3c2-24cc x_refsource_CONFIRM
https://github.com/lightpanda-io/browser/pull/2155 x_refsource_MISC
https://github.com/lightpanda-io/browser/commit/2cdaac780bed65db98bbb6ed2ad5bc6011863c76 x_refsource_MISC
https://github.com/lightpanda-io/browser/releases/tag/0.2.9 x_refsource_MISC