CVE-2026-6754
published 2026-04-21CVE-2026-6754: Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and…
PriorityP340high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
0.39%
31.0th percentile
Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Affected
11 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 150 | Firefox 150 |
| mozilla | firefox | < 115.35.0 | 115.35.0 |
| mozilla | firefox | < 150.0 | 150.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 140.0 < 140.10.0 | 140.10.0 |
| mozilla | firefox_esr | < Firefox ESR 115.35 | Firefox ESR 115.35 |
| mozilla | firefox_esr | < Firefox ESR 140.10 | Firefox ESR 140.10 |
| mozilla | thunderbird | < Thunderbird 150 | Thunderbird 150 |
| mozilla | thunderbird | < Thunderbird 140.10 | Thunderbird 140.10 |
| mozilla | thunderbird | < 140.10.0 | 140.10.0 |
| rhel10 | firefox-flatpak | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vendor_redhat7.5HIGH
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Red Hat
firefox: Use-after-free in the JavaScript Engine component
vendor_redhat·2026-04-21·CVSS 7.5
CVE-2026-6754 [HIGH] CWE-825 firefox: Use-after-free in the JavaScript Engine component
firefox: Use-after-free in the JavaScript Engine component
Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
Use-after-free in the JavaScript Engine 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: firefox (Red Hat Enterprise Linux 6) - Out of support scope
Package: firefox (Red Hat Enterprise Linux 7) - Affected
Package: firefox (R
Mozilla
Mozilla Foundation Security Advisory 2026-31: CVE-2026-6754
vendor_mozilla·CVSS 7.5
CVE-2026-6754 [HIGH] Mozilla Foundation Security Advisory 2026-31: CVE-2026-6754
Mozilla Foundation Security Advisory 2026-31
CVE: CVE-2026-6754
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.35
Mozilla
Mozilla Foundation Security Advisory 2026-33: CVE-2026-6754
vendor_mozilla·CVSS 7.5
CVE-2026-6754 [HIGH] Mozilla Foundation Security Advisory 2026-33: CVE-2026-6754
Mozilla Foundation Security Advisory 2026-33
CVE: CVE-2026-6754
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 150
Mozilla
Mozilla Foundation Security Advisory 2026-34: CVE-2026-6754
vendor_mozilla·CVSS 7.5
CVE-2026-6754 [HIGH] Mozilla Foundation Security Advisory 2026-34: CVE-2026-6754
Mozilla Foundation Security Advisory 2026-34
CVE: CVE-2026-6754
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.10
Mozilla
Mozilla Foundation Security Advisory 2026-32: CVE-2026-6754
vendor_mozilla·CVSS 7.5
CVE-2026-6754 [HIGH] Mozilla Foundation Security Advisory 2026-32: CVE-2026-6754
Mozilla Foundation Security Advisory 2026-32
CVE: CVE-2026-6754
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.10
Mozilla
Mozilla Foundation Security Advisory 2026-30: CVE-2026-6754
vendor_mozilla·CVSS 7.5
CVE-2026-6754 [HIGH] Mozilla Foundation Security Advisory 2026-30: CVE-2026-6754
Mozilla Foundation Security Advisory 2026-30
CVE: CVE-2026-6754
Product: Firefox
Impact: high
Fixed in: Firefox 150
GHSA
GHSA-99hh-xp2q-f3fc: Use-after-free in the JavaScript Engine component
ghsa_unreviewed·2026-04-21
CVE-2026-6754 [HIGH] CWE-416 GHSA-99hh-xp2q-f3fc: Use-after-free in the JavaScript Engine component
Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, and Firefox ESR 140.10.
No detection rules found.
No public exploits indexed.
https://bugzilla.mozilla.org/show_bug.cgi?id=2027541https://www.mozilla.org/security/advisories/mfsa2026-30/https://www.mozilla.org/security/advisories/mfsa2026-31/https://www.mozilla.org/security/advisories/mfsa2026-32/https://www.mozilla.org/security/advisories/mfsa2026-33/https://www.mozilla.org/security/advisories/mfsa2026-34/https://access.redhat.com/errata/RHSA-2026:10757https://access.redhat.com/errata/RHSA-2026:10766https://access.redhat.com/errata/RHSA-2026:10767https://access.redhat.com/errata/RHSA-2026:12285https://access.redhat.com/errata/RHSA-2026:13537https://access.redhat.com/errata/RHSA-2026:15892https://access.redhat.com/errata/RHSA-2026:17477https://access.redhat.com/errata/RHSA-2026:17687https://access.redhat.com/errata/RHSA-2026:17688https://access.redhat.com/errata/RHSA-2026:17689https://access.redhat.com/errata/RHSA-2026:17690https://access.redhat.com/errata/RHSA-2026:19041https://access.redhat.com/errata/RHSA-2026:19131https://access.redhat.com/errata/RHSA-2026:19201https://access.redhat.com/errata/RHSA-2026:19348https://access.redhat.com/errata/RHSA-2026:19461https://access.redhat.com/errata/RHSA-2026:19462https://access.redhat.com/errata/RHSA-2026:19463https://access.redhat.com/errata/RHSA-2026:19464https://access.redhat.com/errata/RHSA-2026:19465https://access.redhat.com/errata/RHSA-2026:19466https://access.redhat.com/errata/RHSA-2026:19467https://access.redhat.com/errata/RHSA-2026:19468https://access.redhat.com/errata/RHSA-2026:19469https://access.redhat.com/errata/RHSA-2026:19542https://access.redhat.com/errata/RHSA-2026:19655https://access.redhat.com/errata/RHSA-2026:19704https://access.redhat.com/security/cve/CVE-2026-6754https://bugzilla.redhat.com/show_bug.cgi?id=2460075https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6754.json
2026-04-21
Published