Vulnerability · Published Apr 21, 2026 · Assigned by mozilla
CVE-2026-6753Incorrect boundary conditions in the WebRTC component
High 7.3
In plain English
A high-severity memory corruption in Firefox from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.3High
Exploit odds (30 days)0.3%top 76.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Incorrect boundary conditions in the WebRTC component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | firefox | 140.10.0-1.el10_1 | ALSA-2026:10767 |
| AlmaLinux:8 | firefox | 140.10.0-1.el8_10.alma.1 | ALSA-2026:10766 |
| AlmaLinux:9 | firefox | 140.10.0-1.el9_7.alma.1 | ALSA-2026:10757 |
| AlmaLinux:9 | firefox-x11 | 140.10.0-1.el9_7.alma.1 | ALSA-2026:10757 |
| AlmaLinux:10 | thunderbird | 140.10.0-1.el10_1.alma.1 | ALSA-2026:12285 |
| AlmaLinux:8 | thunderbird | 140.10.0-1.el8_10.alma.1 | ALSA-2026:13537 |
| AlmaLinux:9 | thunderbird | 140.10.0-1.el9_7.alma.1 | ALSA-2026:15892 |
| AlmaLinux:9 | thunderbird | 140.10.1-1.el9_8.alma.1 | ALSA-2026:19348 |
| Debian:12 | firefox-esr | 140.10.0esr-1~deb12u1 | DEBIAN-CVE-2026-6753 |
| Debian:13 | firefox-esr | 140.10.0esr-1~deb13u1 | DEBIAN-CVE-2026-6753 |
| Debian:14 | firefox-esr | 140.10.0esr-1 | DEBIAN-CVE-2026-6753 |
| Debian:12 | thunderbird | 1:140.10.0esr-1~deb12u1 | DEBIAN-CVE-2026-6753 |
| Debian:13 | thunderbird | 1:140.10.0esr-1~deb13u1 | DEBIAN-CVE-2026-6753 |
| Debian:14 | thunderbird | 1:140.10.0esr-1 | DEBIAN-CVE-2026-6753 |
| Rocky Linux:10 | firefox | 0:140.10.0-1.el10_1 | RLSA-2026:10767 |
| Rocky Linux:8 | firefox | 0:140.10.0-1.el8_10 | RLSA-2026:10766 |
| Rocky Linux:9 | firefox | 0:140.10.0-1.el9_7 | RLSA-2026:19201 |
| Rocky Linux:9 | firefox | 0:140.10.0-1.el9_7 | RLSA-2026:10757 |
| Rocky Linux:10 | thunderbird | 0:140.10.0-1.el10_1 | RLSA-2026:12285 |
| Rocky Linux:8 | thunderbird | 0:140.10.0-1.el8_10 | RLSA-2026:13537 |
| Rocky Linux:9 | thunderbird | 0:140.10.1-1.el9_8 | RLSA-2026:19348 |
| Rocky Linux:9 | thunderbird | 0:140.10.0-1.el9_7 | RLSA-2026:15892 |
| Ubuntu:22.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2026-6753 |
| Ubuntu:24.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2026-6753 |
| Ubuntu:24.04:LTS | mozjs115 | no fix listed | UBUNTU-CVE-2026-6753 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2026-6753 |
| Ubuntu:22.04:LTS | mozjs91 | no fix listed | UBUNTU-CVE-2026-6753 |
| Ubuntu:22.04:LTS | thunderbird | no fix listed | UBUNTU-CVE-2026-6753 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | see references |
| Mozilla | Thunderbird | see references |
Weakness: CWE-119, CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2027501
- https://www.mozilla.org/security/advisories/mfsa2026-30/
- 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/security/cve/CVE-2026-6753 vdb-entry, x_refsource_REDHAT
- RHBZ#2460092 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6753.json x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:19704 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:17690 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19463 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:10767 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:12285 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19041 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19131 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:10766 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:13537 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19655 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19465 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19542 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19466 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:17477 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19467 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:17687 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19468 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:17689 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19461 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19464 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19469 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:17688 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19462 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:10757 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:15892 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19201 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19348 vendor-advisory, x_refsource_REDHAT