Vulnerability · Published Oct 13, 2026 · Assigned by mozilla
CVE-2026-109708Sandbox escape due to incorrect boundary conditions in the Networking component
Critical 9.6
In plain English
A critical-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 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)9.6Critical
Exploit odds (30 days)0.3%top 73.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Sandbox escape due to incorrect boundary conditions in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird 153.5, and Firefox ESR 115.44.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | firefox | 153.5.0-1.el10_2 | ALSA-2026:89758 |
| AlmaLinux:8 | firefox | 153.5.0-1.el8_10 | ALSA-2026:89756 |
| AlmaLinux:9 | firefox | 153.5.0-1.el9_8 | ALSA-2026:89757 |
| AlmaLinux:9 | firefox-x11 | 153.5.0-1.el9_8 | ALSA-2026:89757 |
| AlmaLinux:9 | thunderbird | 153.5.0-1.el9_8.alma.1 | ALSA-2026:93443 |
| Debian:12 | firefox-esr | 153.5.0esr-1~deb12u1 | DEBIAN-CVE-2026-109708 |
| Debian:13 | firefox-esr | 153.5.0esr-1~deb13u1 | DEBIAN-CVE-2026-109708 |
| Debian:14 | firefox-esr | 153.5.0esr-1 | DEBIAN-CVE-2026-109708 |
| Debian:12 | thunderbird | 1:153.5.1esr-1~deb12u1 | DEBIAN-CVE-2026-109708 |
| Debian:13 | thunderbird | 1:153.5.1esr-1~deb13u1 | DEBIAN-CVE-2026-109708 |
| Debian:14 | thunderbird | 1:153.5.0esr-1 | DEBIAN-CVE-2026-109708 |
| Rocky Linux:10 | firefox | 0:153.5.0-1.el10_2 | RLSA-2026:89758 |
| Rocky Linux:8 | firefox | 0:153.5.0-1.el8_10 | RLSA-2026:89756 |
| Rocky Linux:9 | firefox | 0:153.5.0-1.el9_8 | RLSA-2026:89757 |
| Rocky Linux:9 | thunderbird | 0:153.5.0-1.el9_8 | RLSA-2026:93443 |
| Ubuntu:22.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2026-109708 |
| Ubuntu:24.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2026-109708 |
| Ubuntu:24.04:LTS | mozjs115 | no fix listed | UBUNTU-CVE-2026-109708 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2026-109708 |
| Ubuntu:22.04:LTS | mozjs91 | no fix listed | UBUNTU-CVE-2026-109708 |
| Ubuntu:22.04:LTS | thunderbird | no fix listed | UBUNTU-CVE-2026-109708 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | see references |
| Mozilla | Thunderbird | see references |
Weakness: CWE-119 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2059151
- https://www.mozilla.org/security/advisories/mfsa2026-106/
- https://www.mozilla.org/security/advisories/mfsa2026-108/
- https://www.mozilla.org/security/advisories/mfsa2026-109/
- https://www.mozilla.org/security/advisories/mfsa2026-110/
- https://www.mozilla.org/security/advisories/mfsa2026-119/