CVE-2026-4687
published 2026-03-24CVE-2026-4687: Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR…
PriorityP344high8.6CVSS 3.1
AVNACLPRNUINSCCNINAH
EPSS
0.54%
41.7th percentile
Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Affected
11 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | firefox | < firefox 149.0-1 (sid) | firefox 149.0-1 (sid) |
| debian | firefox-esr | < firefox 149.0-1 (sid) | firefox 149.0-1 (sid) |
| debian | thunderbird | < firefox 149.0-1 (sid) | firefox 149.0-1 (sid) |
| mozilla | firefox | < 115.34.0 | 115.34.0 |
| mozilla | firefox | < 149.0 | 149.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 128.0 < 140.9.0 | 140.9.0 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1~deb11u1 | 1:140.9.0esr-1~deb11u1 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1~deb12u1 | 1:140.9.0esr-1~deb12u1 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1~deb13u1 | 1:140.9.0esr-1~deb13u1 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1 | 1:140.9.0esr-1 |
CVSS provenance
nvdv3.18.6HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
osv8.6HIGH
vendor_debian8.6HIGH
vendor_redhat8.6HIGH
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Red Hat
firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Telemetry component
vendor_redhat·2026-03-24·CVSS 8.6
CVE-2026-4687 [HIGH] CWE-501 firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Telemetry component
firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Telemetry component
Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Sandbox escape due to incorrect boundary conditions in the Telemetry component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Affected
Package:
Debian
CVE-2026-4687: firefox - Sandbox escape due to incorrect boundary conditions in the Telemetry component. ...
vendor_debian·2026·CVSS 8.6
CVE-2026-4687 [HIGH] CVE-2026-4687: firefox - Sandbox escape due to incorrect boundary conditions in the Telemetry component. ...
Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
Scope: local
sid: resolved (fixed in 149.0-1)
Mozilla
Mozilla Foundation Security Advisory 2026-22: CVE-2026-4687
vendor_mozilla·CVSS 8.6
CVE-2026-4687 [HIGH] Mozilla Foundation Security Advisory 2026-22: CVE-2026-4687
Mozilla Foundation Security Advisory 2026-22
CVE: CVE-2026-4687
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.9
Mozilla
Mozilla Foundation Security Advisory 2026-23: CVE-2026-4687
vendor_mozilla·CVSS 8.6
CVE-2026-4687 [HIGH] Mozilla Foundation Security Advisory 2026-23: CVE-2026-4687
Mozilla Foundation Security Advisory 2026-23
CVE: CVE-2026-4687
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 149
Mozilla
Mozilla Foundation Security Advisory 2026-24: CVE-2026-4687
vendor_mozilla·CVSS 8.6
CVE-2026-4687 [HIGH] Mozilla Foundation Security Advisory 2026-24: CVE-2026-4687
Mozilla Foundation Security Advisory 2026-24
CVE: CVE-2026-4687
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.9
Mozilla
Mozilla Foundation Security Advisory 2026-20: CVE-2026-4687
vendor_mozilla·CVSS 8.6
CVE-2026-4687 [HIGH] Mozilla Foundation Security Advisory 2026-20: CVE-2026-4687
Mozilla Foundation Security Advisory 2026-20
CVE: CVE-2026-4687
Product: Firefox
Impact: high
Fixed in: Firefox 149
Mozilla
Mozilla Foundation Security Advisory 2026-21: CVE-2026-4687
vendor_mozilla·CVSS 8.6
CVE-2026-4687 [HIGH] Mozilla Foundation Security Advisory 2026-21: CVE-2026-4687
Mozilla Foundation Security Advisory 2026-21
CVE: CVE-2026-4687
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.34
OSV
CVE-2026-4687: Sandbox escape due to incorrect boundary conditions in the Telemetry component
osv·2026-03-24·CVSS 8.6
CVE-2026-4687 [HIGH] CVE-2026-4687: Sandbox escape due to incorrect boundary conditions in the Telemetry component
Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
GHSA
GHSA-gw7x-g9xx-wmm2: Sandbox escape due to incorrect boundary conditions in the Telemetry component
ghsa_unreviewed·2026-03-24
CVE-2026-4687 [HIGH] CWE-120 GHSA-gw7x-g9xx-wmm2: Sandbox escape due to incorrect boundary conditions in the Telemetry component
Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-4687 firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Telemetry component
bugzilla·2026-03-24·CVSS 8.6
CVE-2026-4687 [HIGH] CVE-2026-4687 firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Telemetry component
CVE-2026-4687 firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Telemetry component
Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 10
Via RHSA-2026:5931 https://access.redhat.com/errata/RHSA-2026:5931
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2026:5930 https://access.redhat.com/errata/RHSA-2026:5930
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2026:5932 https://access.redhat.com/errata/RHSA-2026:5932
---
This issue has been add
Wiz
CVE-2026-4687 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 7.5
CVE-2026-4687 [HIGH] CVE-2026-4687 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-4687 :
NixOS vulnerability analysis and mitigation
Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
Source : NVD
## 8.6
Score
Published March 24, 2026
Severity HIGH
CNA Score 9.6
Affected Technologies
NixOS
Mozilla Firefox
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 6.4
Exploitation Probability (EPSS) N/A
Affected packages and libraries
MozillaFirefox-branding-upstream
cpe:2.3:a:mozilla:firefox
Sources
AlmaLinux 8 Severity HIGH Has Fix Added at: Mar 31, 2026
AlmaLinux 9 Severity HIGH Has Fix Added at: Mar
https://bugzilla.mozilla.org/show_bug.cgi?id=2016368https://www.mozilla.org/security/advisories/mfsa2026-20/https://www.mozilla.org/security/advisories/mfsa2026-21/https://www.mozilla.org/security/advisories/mfsa2026-22/https://www.mozilla.org/security/advisories/mfsa2026-23/https://www.mozilla.org/security/advisories/mfsa2026-24/https://access.redhat.com/errata/RHSA-2026:5930https://access.redhat.com/errata/RHSA-2026:5931https://access.redhat.com/errata/RHSA-2026:5932https://access.redhat.com/errata/RHSA-2026:6188https://access.redhat.com/errata/RHSA-2026:6342https://access.redhat.com/errata/RHSA-2026:6917https://access.redhat.com/errata/RHSA-2026:7837https://access.redhat.com/errata/RHSA-2026:7838https://access.redhat.com/errata/RHSA-2026:7839https://access.redhat.com/errata/RHSA-2026:7840https://access.redhat.com/errata/RHSA-2026:7841https://access.redhat.com/errata/RHSA-2026:7842https://access.redhat.com/errata/RHSA-2026:7843https://access.redhat.com/errata/RHSA-2026:7845https://access.redhat.com/errata/RHSA-2026:7858https://access.redhat.com/errata/RHSA-2026:8284https://access.redhat.com/errata/RHSA-2026:8285https://access.redhat.com/errata/RHSA-2026:8286https://access.redhat.com/errata/RHSA-2026:8287https://access.redhat.com/errata/RHSA-2026:8288https://access.redhat.com/errata/RHSA-2026:8289https://access.redhat.com/errata/RHSA-2026:8290https://access.redhat.com/errata/RHSA-2026:8315https://access.redhat.com/errata/RHSA-2026:8427https://access.redhat.com/errata/RHSA-2026:8850https://access.redhat.com/security/cve/CVE-2026-4687https://bugzilla.redhat.com/show_bug.cgi?id=2450757https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4687.json
2026-03-24
Published