How severe is CVE-2026-6778?

CVE-2026-6778 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2026-6778 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-6778?

CVE-2026-6778 primarily affects Mozilla Firefox. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-6778?

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

Does CVE-2026-6778 have an EU (EUVD) identifier?

Yes. CVE-2026-6778 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24119.

When was CVE-2026-6778 published?

CVE-2026-6778 was published on 2026-04-21 and last updated on 2026-06-17.

CVE-2026-6778

CVE-2026-6778 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 5.3. 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-476.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (17th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24119
Weakness: CWE-476
Affected product: Mozilla Firefox
Published: 2026-04-21
Last modified: 2026-06-17

Description

Invalid pointer in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

Frequently asked questions

What is CVE-2026-6778?: Invalid pointer in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.
How severe is CVE-2026-6778?: CVE-2026-6778 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2026-6778 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-6778?: CVE-2026-6778 primarily affects Mozilla Firefox. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-6778?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-6778 have an EU (EUVD) identifier?: Yes. CVE-2026-6778 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24119.
When was CVE-2026-6778 published?: CVE-2026-6778 was published on 2026-04-21 and last updated on 2026-06-17.

References

Affected products (2)

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

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