CVE-2026-6748

CRITICAL
Published Apr 21, 2026 Modified Apr 22, 2026 CWE-457

Description

Uninitialized memory in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

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CVSS v3.1 Score

9.8
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0006
Probability of exploitation
0.20%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-457 CWE-457

Affected Products

Vendor Product
mozilla firefox
mozilla firefox
mozilla thunderbird

References

Frequently Asked Questions

What is CVE-2026-6748? +
Uninitialized memory in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. It has a CVSS v3.1 base score of 9.8 (CRITICAL).
How severe is CVE-2026-6748? +
CVE-2026-6748 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0006, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-6748? +
CVE-2026-6748 affects products from mozilla, specifically: firefox, thunderbird. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-6748? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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