How severe is CVE-2026-52843?

CVE-2026-52843 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-52843 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-52843?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-52843 published?

CVE-2026-52843 was published on 2026-07-15.

CVE-2026-52843

CVE-2026-52843 is a critical-severity vulnerability with a CVSS 3.x base score of 9.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-346.

Key facts

Severity: Critical (CVSS 3.x base score 9.3)
EPSS exploit prediction: 0% (7th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-346
Published: 2026-07-15
Last modified: 2026-07-15

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.

Frequently asked questions

What is CVE-2026-52843?: 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.
How severe is CVE-2026-52843?: CVE-2026-52843 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-52843 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-52843?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-52843 published?: CVE-2026-52843 was published on 2026-07-15.

References

Other CWE-346 vulnerabilities

CVE-2026-42901 — Critical (CVSS 10.0): Origin validation error in Microsoft Entra ID allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-16375 — Critical (CVSS 9.8): Site isolation issue in the Networking: HTTP component. This vulnerability was fixed in Firefox 153, Firefox ESR…
CVE-2026-16358 — Critical (CVSS 9.8): Site isolation issue in the Graphics: WebRender component. This vulnerability was fixed in Firefox 153, Firefox ESR…
CVE-2026-16349 — Critical (CVSS 9.8): Same-origin policy bypass in the DOM: Navigation component. This vulnerability was fixed in Firefox 153, Firefox ESR…
CVE-2023-49899 — Critical (CVSS 9.8): An unauthenticated remote attacker can execute any command on the affected device due to not correctly verifying the…
CVE-2026-6508 — Critical (CVSS 9.8): Origin Validation Error vulnerability in TUBITAK BILGEM Software Technologies Research Institute Liderahenk allows…

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