How severe is CVE-2026-6763?

CVE-2026-6763 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-2026-6763 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-6763?

CVE-2026-6763 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-6763?

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

Does CVE-2026-6763 have an EU (EUVD) identifier?

Yes. CVE-2026-6763 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24104.

When was CVE-2026-6763 published?

CVE-2026-6763 was published on 2026-04-21 and last updated on 2026-06-17.

CVE-2026-6763

CVE-2026-6763 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-693.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (9th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24104
Weakness: CWE-693
Affected product: Mozilla Firefox
Published: 2026-04-21
Last modified: 2026-06-17

Description

Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

Frequently asked questions

What is CVE-2026-6763?: Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
How severe is CVE-2026-6763?: CVE-2026-6763 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-2026-6763 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-6763?: CVE-2026-6763 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-6763?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-6763 have an EU (EUVD) identifier?: Yes. CVE-2026-6763 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24104.
When was CVE-2026-6763 published?: CVE-2026-6763 was published on 2026-04-21 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*

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