CVE-2026-74958CWE-1021

CVE-2026-74958

High · published August 18, 2026

CVSS v3.1

7.5

EPSS

Percentile

38.3

In the wild

Unconfirmed

What it is

Information disclosure in the WebRTC component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.

The record

Technical detail

CVSS v3.1: 7.5 · HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0: Not supplied
EPSS: 0.00452 · 38.3th percentile
Weakness: CWE-1021 · Improper Restriction of Rendered UI Layers or Frames
Published: 2026-08-18T17:17Z

Affected products (4)

Product	Versions	Fixed in
mozilla/firefox	< 153.1.0	153.1.0
mozilla/firefox	< 154.0.0	154.0.0
mozilla/thunderbird	< 153.1.0	153.1.0
mozilla/thunderbird	< 154.0	154.0

References (5)

https://bugzilla.mozilla.org/show_bug.cgi?id=2045368 · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-74/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-77/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-78/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-80/ · [email protected]

EPSS history

Timeline

18 AUG 12:23Z
Information disclosure in the WebRTC component
cvelistv5