Information disclosure, sandbox escape in the Security: Process Sandboxing component
Published May 19, 2026
8.6
HIGHCVSS 3.1
EPSS 0.44%
Description
Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Affected products
No data.
- < 140.11.0
- < 151.0.0
- < 140.11
- < 151.0.0
No data.
Red Hat Enterprise Linux 10
firefox-0:140.11.0-1.el10_2
Fixed · RHSA-2026:21380
Red Hat Enterprise Linux 10
thunderbird-0:140.11.0-1.el10_2
Fixed · RHSA-2026:22325
Red Hat Enterprise Linux 10.0 Extended Update Support
firefox-0:140.11.0-1.el10_0
Fixed · RHSA-2026:27715
Red Hat Enterprise Linux 10.0 Extended Update Support
thunderbird-0:140.11.0-1.el10_0
Fixed · RHSA-2026:26539
Red Hat Enterprise Linux 7 Extended Lifecycle Support
firefox-0:140.11.0-1.el7_9
Fixed · RHSA-2026:26551
Red Hat Enterprise Linux 8
firefox-0:140.11.0-1.el8_10
Fixed · RHSA-2026:21382
Red Hat Enterprise Linux 8
thunderbird-0:140.11.0-1.el8_10
Fixed · RHSA-2026:22643
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
firefox-0:140.11.0-1.el8_4
Fixed · RHSA-2026:26629
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
thunderbird-0:140.11.0-1.el8_4
Fixed · RHSA-2026:26270
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
firefox-0:140.11.0-1.el8_4
Fixed · RHSA-2026:26629
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
thunderbird-0:140.11.0-1.el8_4
Fixed · RHSA-2026:26270
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
firefox-0:140.11.0-1.el8_6
Fixed · RHSA-2026:26606
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
thunderbird-0:140.11.0-1.el8_6
Fixed · RHSA-2026:26536
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
firefox-0:140.11.0-1.el8_6
Fixed · RHSA-2026:26606
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
thunderbird-0:140.11.0-1.el8_6
Fixed · RHSA-2026:26536
Red Hat Enterprise Linux 8.8 Telecommunications Update Service
firefox-0:140.11.0-1.el8_8
Fixed · RHSA-2026:26630
Red Hat Enterprise Linux 8.8 Telecommunications Update Service
thunderbird-0:140.11.0-1.el8_8
Fixed · RHSA-2026:26268
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
firefox-0:140.11.0-1.el8_8
Fixed · RHSA-2026:26630
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
thunderbird-0:140.11.0-1.el8_8
Fixed · RHSA-2026:26268
Red Hat Enterprise Linux 9
firefox-0:140.11.0-1.el9_8
Fixed · RHSA-2026:21378
Red Hat Enterprise Linux 9
thunderbird-0:140.11.0-1.el9_8
Fixed · RHSA-2026:21381
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
firefox-0:140.11.0-1.el9_2
Fixed · RHSA-2026:26491
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
thunderbird-0:140.11.0-1.el9_2
Fixed · RHSA-2026:26269
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
firefox-0:140.11.0-1.el9_4
Fixed · RHSA-2026:26493
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
thunderbird-0:140.11.0-1.el9_4
Fixed · RHSA-2026:26174
Red Hat Enterprise Linux 9.6 Extended Update Support
firefox-0:140.11.0-1.el9_6
Fixed · RHSA-2026:26492
Red Hat Enterprise Linux 9.6 Extended Update Support
thunderbird-0:140.11.0-1.el9_6
Fixed · RHSA-2026:26521
Red Hat Enterprise Linux 10
rhel10/firefox-flatpak
Affected
Red Hat Enterprise Linux 10
rhel10/thunderbird-flatpak
Affected
Red Hat Enterprise Linux 6
firefox
Out of support scope
Red Hat Enterprise Linux 6
thunderbird
Out of support scope
Red Hat Enterprise Linux 7
thunderbird
Out of support scope
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | firefox-0:140.11.0-1.el10_2 | Fixed | RHSA-2026:21380 |
| Red Hat Enterprise Linux 10 | thunderbird-0:140.11.0-1.el10_2 | Fixed | RHSA-2026:22325 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | firefox-0:140.11.0-1.el10_0 | Fixed | RHSA-2026:27715 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | thunderbird-0:140.11.0-1.el10_0 | Fixed | RHSA-2026:26539 |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | firefox-0:140.11.0-1.el7_9 | Fixed | RHSA-2026:26551 |
| Red Hat Enterprise Linux 8 | firefox-0:140.11.0-1.el8_10 | Fixed | RHSA-2026:21382 |
| Red Hat Enterprise Linux 8 | thunderbird-0:140.11.0-1.el8_10 | Fixed | RHSA-2026:22643 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | firefox-0:140.11.0-1.el8_4 | Fixed | RHSA-2026:26629 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | thunderbird-0:140.11.0-1.el8_4 | Fixed | RHSA-2026:26270 |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | firefox-0:140.11.0-1.el8_4 | Fixed | RHSA-2026:26629 |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | thunderbird-0:140.11.0-1.el8_4 | Fixed | RHSA-2026:26270 |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | firefox-0:140.11.0-1.el8_6 | Fixed | RHSA-2026:26606 |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | thunderbird-0:140.11.0-1.el8_6 | Fixed | RHSA-2026:26536 |
| Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | firefox-0:140.11.0-1.el8_6 | Fixed | RHSA-2026:26606 |
| Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | thunderbird-0:140.11.0-1.el8_6 | Fixed | RHSA-2026:26536 |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | firefox-0:140.11.0-1.el8_8 | Fixed | RHSA-2026:26630 |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | thunderbird-0:140.11.0-1.el8_8 | Fixed | RHSA-2026:26268 |
| Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | firefox-0:140.11.0-1.el8_8 | Fixed | RHSA-2026:26630 |
| Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | thunderbird-0:140.11.0-1.el8_8 | Fixed | RHSA-2026:26268 |
| Red Hat Enterprise Linux 9 | firefox-0:140.11.0-1.el9_8 | Fixed | RHSA-2026:21378 |
| Red Hat Enterprise Linux 9 | thunderbird-0:140.11.0-1.el9_8 | Fixed | RHSA-2026:21381 |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | firefox-0:140.11.0-1.el9_2 | Fixed | RHSA-2026:26491 |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | thunderbird-0:140.11.0-1.el9_2 | Fixed | RHSA-2026:26269 |
| Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | firefox-0:140.11.0-1.el9_4 | Fixed | RHSA-2026:26493 |
| Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | thunderbird-0:140.11.0-1.el9_4 | Fixed | RHSA-2026:26174 |
| Red Hat Enterprise Linux 9.6 Extended Update Support | firefox-0:140.11.0-1.el9_6 | Fixed | RHSA-2026:26492 |
| Red Hat Enterprise Linux 9.6 Extended Update Support | thunderbird-0:140.11.0-1.el9_6 | Fixed | RHSA-2026:26521 |
| Red Hat Enterprise Linux 10 | rhel10/firefox-flatpak | Affected | n/a |
| Red Hat Enterprise Linux 10 | rhel10/thunderbird-flatpak | Affected | n/a |
| Red Hat Enterprise Linux 6 | firefox | Out of support scope | n/a |
| Red Hat Enterprise Linux 6 | thunderbird | Out of support scope | n/a |
| Red Hat Enterprise Linux 7 | thunderbird | Out of support scope | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
References (12)
- https://access.redhat.com/security/cve/CVE-2026-8958 Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=2034713 Permissions Required
- https://bugzilla.redhat.com/show_bug.cgi?id=2479848 Issue Tracking
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-30907 Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2026-8958
- https://www.cve.org/CVERecord?id=CVE-2026-8958
- https://www.mozilla.org/security/advisories/mfsa2026-46/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-48/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-48/#CVE-2026-8958
- https://www.mozilla.org/security/advisories/mfsa2026-50/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-51/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-51/#CVE-2026-8958
Change history (0)
No recorded changes yet.