What is CVE-2026-100783?

CVE-2026-100783 is a medium-severity vulnerability, classified under CWE-457. CVSS score: 4.3/10. Published 2026-09-29.

How severe is CVE-2026-100783?

Medium severity. CVSS v3 base score is 4.3 out of 10.

CVE-2026-100783

CVE-2026-100783

Uninitialized memory in the Audio/Video component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

Published 2026-09-29 · last modified 2026-09-29.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Weakness classification (CWE)

CWE-457

References

bugzilla.mozilla.org/show_bug.cgi
www.mozilla.org/security/advisories/mfsa2026-100/
www.mozilla.org/security/advisories/mfsa2026-97/
www.mozilla.org/security/advisories/mfsa2026-98/
www.mozilla.org/security/advisories/mfsa2026-99/

Frequently asked questions

What is CVE-2026-100783?: CVE-2026-100783 is a medium-severity vulnerability, classified under CWE-457. CVSS score: 4.3/10. Published 2026-09-29.
How severe is CVE-2026-100783?: Medium severity. CVSS v3 base score is 4.3 out of 10.