CVE-2026-84122
published 2026-09-01CVE-2026-84122: Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird…
PriorityP426medium5.4CVSS 3.1
AVNACLPRNUIRSUCLILAN
EPSS
0.21%
11.7th percentile
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
Affected
16 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 155 | Firefox 155 |
| mozilla | firefox | < 140.15.0 | 140.15.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 141.0.0 < 153.2.0 | 153.2.0 |
| mozilla | firefox | >= 154.0.0 < 155.0.0 | 155.0.0 |
| mozilla | firefox_esr | < Firefox ESR 140.15 | Firefox ESR 140.15 |
| mozilla | firefox_esr | < Firefox ESR 153.2 | Firefox ESR 153.2 |
| mozilla | thunderbird | < Thunderbird 153.2 | Thunderbird 153.2 |
| mozilla | thunderbird | < Thunderbird 155 | Thunderbird 155 |
| mozilla | thunderbird | < Thunderbird 140.15 | Thunderbird 140.15 |
| mozilla | thunderbird | < 140.15.0 | 140.15.0 |
| mozilla | thunderbird | — | — |
| mozilla | thunderbird | >= 141.0 < 153.2.0 | 153.2.0 |
| mozilla | thunderbird | >= 154.0 < 155.0 | 155.0 |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
CVSS provenance
nvdv3.15.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
vendor_redhat5.4MEDIUM
Stop checking back — get the weekly exploitation signal.
Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.
GHSA
Use-after-free in the Audio/Video component.
ghsa_unreviewed·2026-09-01
CVE-2026-84122 [MEDIUM] CWE-416 Use-after-free in the Audio/Video component.
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, and Firefox ESR 153.2.
Red Hat
firefox: Use-after-free in the Audio/Video component
vendor_redhat·2026-09-01·CVSS 5.4
CVE-2026-84122 [MEDIUM] CWE-825 firefox: Use-after-free in the Audio/Video component
firefox: Use-after-free in the Audio/Video component
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
Use-after-free in the Audio/Video component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: firefox (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: thunderbird (Red Hat Enterprise Linux 10) - Affected
Packag
Mozilla
Mozilla Foundation Security Advisory 2026-84: CVE-2026-84122
vendor_mozilla·CVSS 5.4
CVE-2026-84122 [MEDIUM] Mozilla Foundation Security Advisory 2026-84: CVE-2026-84122
Mozilla Foundation Security Advisory 2026-84
CVE: CVE-2026-84122
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.15
Mozilla
Mozilla Foundation Security Advisory 2026-88: CVE-2026-84122
vendor_mozilla·CVSS 5.4
CVE-2026-84122 [MEDIUM] Mozilla Foundation Security Advisory 2026-88: CVE-2026-84122
Mozilla Foundation Security Advisory 2026-88
CVE: CVE-2026-84122
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 153.2
Mozilla
Mozilla Foundation Security Advisory 2026-82: CVE-2026-84122
vendor_mozilla·CVSS 5.4
CVE-2026-84122 [MEDIUM] Mozilla Foundation Security Advisory 2026-82: CVE-2026-84122
Mozilla Foundation Security Advisory 2026-82
CVE: CVE-2026-84122
Product: Firefox
Impact: high
Fixed in: Firefox 155
Mozilla
Mozilla Foundation Security Advisory 2026-86: CVE-2026-84122
vendor_mozilla·CVSS 5.4
CVE-2026-84122 [MEDIUM] Mozilla Foundation Security Advisory 2026-86: CVE-2026-84122
Mozilla Foundation Security Advisory 2026-86
CVE: CVE-2026-84122
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 155
Mozilla
Mozilla Foundation Security Advisory 2026-85: CVE-2026-84122
vendor_mozilla·CVSS 5.4
CVE-2026-84122 [MEDIUM] Mozilla Foundation Security Advisory 2026-85: CVE-2026-84122
Mozilla Foundation Security Advisory 2026-85
CVE: CVE-2026-84122
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 153.2
Mozilla
Mozilla Foundation Security Advisory 2026-87: CVE-2026-84122
vendor_mozilla·CVSS 5.4
CVE-2026-84122 [MEDIUM] Mozilla Foundation Security Advisory 2026-87: CVE-2026-84122
Mozilla Foundation Security Advisory 2026-87
CVE: CVE-2026-84122
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.15
No detection rules found.
No public exploits indexed.
Hackernews
⚡ Weekly Recap: Chrome 0-Day, Router Hijacks, Coder Supply Chain Attack and More
blogs_hackernews·2026-09-07·CVSS 6.9
CVE-2026-86206 [MEDIUM] ⚡ Weekly Recap: Chrome 0-Day, Router Hijacks, Coder Supply Chain Attack and More
Home
Threat Intelligence
Vulnerabilities
Cyber Attacks
Webinars
Expert Insights
Awards
Webinars
Awards
Free eBooks
About THN
Jobs
Advertise with us
## ⚡ Weekly Recap: Chrome 0-Day, Router Hijacks, Coder Supply Chain Attack and More
Turning off email images should at least stop the pictures. This week, attackers had a workaround: a scannable QR code built out of text. It still appears, even with images blocked. A small detail, but an annoying one if that was a precaution you were counting on.
Elsewhere, a trusted software source delivered code that stole credentials, and a protocol designed for secure network management gave outsiders useful clues before login. Add active attacks on browsers, routers, and online stores, and there’s plenty to check—even for teams that have k
Bugzilla
CVE-2026-84122 firefox: Use-after-free in the Audio/Video component
bugzilla·2026-09-01·CVSS 5.4
CVE-2026-84122 [MEDIUM] CVE-2026-84122 firefox: Use-after-free in the Audio/Video component
CVE-2026-84122 firefox: Use-after-free in the Audio/Video component
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, and Firefox ESR 153.2.
https://bugzilla.mozilla.org/show_bug.cgi?id=2059965https://www.mozilla.org/security/advisories/mfsa2026-82/https://www.mozilla.org/security/advisories/mfsa2026-84/https://www.mozilla.org/security/advisories/mfsa2026-85/https://www.mozilla.org/security/advisories/mfsa2026-86/https://www.mozilla.org/security/advisories/mfsa2026-87/https://www.mozilla.org/security/advisories/mfsa2026-88/
2026-09-01
Published