How severe is CVE-2026-11326?

CVE-2026-11326 has a CVSS 4.0 base score of 6.0, rated medium severity.

Is CVE-2026-11326 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-11326?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-11326 have an EU (EUVD) identifier?

Yes. CVE-2026-11326 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-34776.

When was CVE-2026-11326 published?

CVE-2026-11326 was published on 2026-06-05 and last updated on 2026-06-17.

CVE-2026-11326

CVE-2026-11326 is a medium-severity vulnerability with a CVSS 4.0 base score of 6.0. 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-284.

Key facts

Severity: Medium (CVSS 4.0 base score 6.0)
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-34776
Weakness: CWE-284
Published: 2026-06-05
Last modified: 2026-06-17

Description

OpenAI Atlas before 1.2025.288.15 exposed privileged browser APIs to web content on *.openai.com origins. A cross-site scripting vulnerability in forum.openai.com could be used to access these functions, allowing access to browser history information and the ability to open or close tabs. OpenAI Atlas 1.2025.288.15 narrows access to these APIs to *.chatgpt.com; users should upgrade to 1.2025.288.15 or later.

Frequently asked questions

What is CVE-2026-11326?: OpenAI Atlas before 1.2025.288.15 exposed privileged browser APIs to web content on *.openai.com origins. A cross-site scripting vulnerability in forum.openai.com could be used to access these functions, allowing access to browser history information and the ability to open or close tabs. OpenAI Atlas 1.2025.288.15 narrows access to these APIs to *.chatgpt.com; users should upgrade to 1.2025.288.15 or later.
How severe is CVE-2026-11326?: CVE-2026-11326 has a CVSS 4.0 base score of 6.0, rated medium severity.
Is CVE-2026-11326 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-11326?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-11326 have an EU (EUVD) identifier?: Yes. CVE-2026-11326 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-34776.
When was CVE-2026-11326 published?: CVE-2026-11326 was published on 2026-06-05 and last updated on 2026-06-17.

References

https://www.hacktron.ai/blog/hacking-openai-atlas-browser

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