CVE-2026-74936
published 2026-08-18CVE-2026-74936: Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154…
PriorityP352critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
0.59%
47.6th percentile
Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Affected
14 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 154 | Firefox 154 |
| mozilla | firefox | < 140.14.0 | 140.14.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 141.0.0 < 153.1.0 | 153.1.0 |
| mozilla | firefox_esr | < Firefox ESR 140.14 | Firefox ESR 140.14 |
| mozilla | firefox_esr | < Firefox ESR 153.1 | Firefox ESR 153.1 |
| mozilla | thunderbird | < Thunderbird 140.14 | Thunderbird 140.14 |
| mozilla | thunderbird | < Thunderbird 153.1 | Thunderbird 153.1 |
| mozilla | thunderbird | < Thunderbird 154 | Thunderbird 154 |
| mozilla | thunderbird | < 140.14.0 | 140.14.0 |
| mozilla | thunderbird | — | — |
| mozilla | thunderbird | >= 141.0 < 153.1.0 | 153.1.0 |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
CVSS provenance
nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vendor_redhat7.5HIGH
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Red Hat
firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component
vendor_redhat·2026-08-18·CVSS 7.5
CVE-2026-74936 [HIGH] CWE-825 firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component
firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Use-after-free in the JavaScript: WebAssembly 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
Package: firefox (Red Hat Enterprise Linux 6) - Out of support scope
Package: thunderbird (Red Hat Enterprise Linux 6) - Out of support scope
Mozilla
Mozilla Foundation Security Advisory 2026-79: CVE-2026-74936
vendor_mozilla
CVE-2026-74936 Mozilla Foundation Security Advisory 2026-79: CVE-2026-74936
Mozilla Foundation Security Advisory 2026-79
CVE: CVE-2026-74936
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.14
Mozilla
Mozilla Foundation Security Advisory 2026-80: CVE-2026-74936
vendor_mozilla
CVE-2026-74936 Mozilla Foundation Security Advisory 2026-80: CVE-2026-74936
Mozilla Foundation Security Advisory 2026-80
CVE: CVE-2026-74936
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 153.1
Mozilla
Mozilla Foundation Security Advisory 2026-76: CVE-2026-74936
vendor_mozilla
CVE-2026-74936 Mozilla Foundation Security Advisory 2026-76: CVE-2026-74936
Mozilla Foundation Security Advisory 2026-76
CVE: CVE-2026-74936
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.14
Mozilla
Mozilla Foundation Security Advisory 2026-78: CVE-2026-74936
vendor_mozilla
CVE-2026-74936 Mozilla Foundation Security Advisory 2026-78: CVE-2026-74936
Mozilla Foundation Security Advisory 2026-78
CVE: CVE-2026-74936
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 154
Mozilla
Mozilla Foundation Security Advisory 2026-77: CVE-2026-74936
vendor_mozilla
CVE-2026-74936 Mozilla Foundation Security Advisory 2026-77: CVE-2026-74936
Mozilla Foundation Security Advisory 2026-77
CVE: CVE-2026-74936
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 153.1
Mozilla
Mozilla Foundation Security Advisory 2026-74: CVE-2026-74936
vendor_mozilla
CVE-2026-74936 Mozilla Foundation Security Advisory 2026-74: CVE-2026-74936
Mozilla Foundation Security Advisory 2026-74
CVE: CVE-2026-74936
Product: Firefox
Impact: high
Fixed in: Firefox 154
VulDB
Mozilla Firefox up to 140.13/153/153.0 WebAssembly use after free (Nessus ID 337931)
vuldb·2026-08-23·CVSS 9.8
CVE-2026-74936 [CRITICAL] Mozilla Firefox up to 140.13/153/153.0 WebAssembly use after free (Nessus ID 337931)
A vulnerability categorized as critical has been discovered in Mozilla Firefox up to 140.13/153/153.0. Affected is an unknown function of the component WebAssembly. Executing a manipulation can lead to use after free.
This vulnerability appears as CVE-2026-74936. The attack may be performed from remote. There is no available exploit.
It is advisable to upgrade the affected component.
GHSA
Use-after-free in the JavaScript: WebAssembly component.
ghsa_unreviewed·2026-08-18
CVE-2026-74936 Use-after-free in the JavaScript: WebAssembly component.
Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.
No detection rules found.
No public exploits indexed.
Hackernews
⚡ Weekly Recap: AI-Powered PLC Attacks, GitLab Attacks, Stripe Key Leaks and More
blogs_hackernews·2026-08-24
CVE-2026-19478 ⚡ Weekly Recap: AI-Powered PLC Attacks, GitLab Attacks, Stripe Key Leaks and More
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## ⚡ Weekly Recap: AI-Powered PLC Attacks, GitLab Attacks, Stripe Key Leaks and More
A package gets installed. A login prompt opens. A box sits exposed to the internet. Nothing looks unusual yet.
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Plenty to clean up. Here’s the short version.
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Bugzilla
CVE-2026-74936 firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component
bugzilla·2026-08-18
CVE-2026-74936 [HIGH] CVE-2026-74936 firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component
CVE-2026-74936 firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component
Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.
https://bugzilla.mozilla.org/show_bug.cgi?id=2052688https://www.mozilla.org/security/advisories/mfsa2026-74/https://www.mozilla.org/security/advisories/mfsa2026-76/https://www.mozilla.org/security/advisories/mfsa2026-77/https://www.mozilla.org/security/advisories/mfsa2026-78/https://www.mozilla.org/security/advisories/mfsa2026-79/https://www.mozilla.org/security/advisories/mfsa2026-80/
2026-08-18
Published