How severe is CVE-2024-9391?

CVE-2024-9391 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2024-9391 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-9391?

CVE-2024-9391 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2024-9391?

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

Does CVE-2024-9391 have an EU (EUVD) identifier?

Yes. CVE-2024-9391 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-50307.

When was CVE-2024-9391 published?

CVE-2024-9391 was published on 2024-10-01 and last updated on 2026-06-17.

CVE-2024-9391

CVE-2024-9391 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 6.5. 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-290.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (20th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-50307
Weakness: CWE-290
Affected product: Mozilla Firefox
Published: 2024-10-01
Last modified: 2026-06-17

Description

A user who enables full-screen mode on a specially crafted web page could potentially be prevented from exiting full screen mode. This may allow spoofing of other sites as the address bar is no longer visible. *This bug only affects Firefox Focus for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox < 131.

Frequently asked questions

What is CVE-2024-9391?: A user who enables full-screen mode on a specially crafted web page could potentially be prevented from exiting full screen mode. This may allow spoofing of other sites as the address bar is no longer visible. *This bug only affects Firefox Focus for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox < 131.
How severe is CVE-2024-9391?: CVE-2024-9391 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2024-9391 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-9391?: CVE-2024-9391 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-9391?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-9391 have an EU (EUVD) identifier?: Yes. CVE-2024-9391 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-50307.
When was CVE-2024-9391 published?: CVE-2024-9391 was published on 2024-10-01 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*

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