Same-origin policy bypass in the Networking: JAR component
Published May 19, 2026
6.5
MEDIUMCVSS 3.1
EPSS 0.17%
Description
Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
Affected products
No data.
- < 151.0.0
- < 151.0.0
No data.
Red Hat Enterprise Linux 10
firefox
Not affected
Red Hat Enterprise Linux 10
rhel10/firefox-flatpak
Not affected
Red Hat Enterprise Linux 10
rhel10/thunderbird-flatpak
Not affected
Red Hat Enterprise Linux 10
thunderbird
Not affected
Red Hat Enterprise Linux 6
firefox
Not affected
Red Hat Enterprise Linux 6
thunderbird
Not affected
Red Hat Enterprise Linux 7
firefox
Not affected
Red Hat Enterprise Linux 7
thunderbird
Not affected
Red Hat Enterprise Linux 8
firefox
Not affected
Red Hat Enterprise Linux 8
thunderbird
Not affected
Red Hat Enterprise Linux 9
firefox
Not affected
Red Hat Enterprise Linux 9
thunderbird
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 10 | rhel10/firefox-flatpak | Not affected | n/a |
| Red Hat Enterprise Linux 10 | rhel10/thunderbird-flatpak | Not affected | n/a |
| Red Hat Enterprise Linux 10 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 6 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 6 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 7 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 7 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 8 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 8 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 9 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 9 | thunderbird | Not affected | 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.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
1 other source (Red Hat) ▾
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
YesTechnical Impact
PartialDecision
n/aAssessed May 19, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 3, 2026.
Score over time
May–Oct 2026- EPSS v4
- EPSS v5
Percentile over time
- EPSS v4
- EPSS v5
Table of values (3 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 3, 2026 | 0.17% (0.00174) | 6.17th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.15% (0.00147) | 4.28th | v5 (v2026.06.15) |
| May 20, 2026 | 0.01% (0.00014) | 2.58th | v4 (v2025.03.14) |
References (9)
- https://access.redhat.com/security/cve/CVE-2026-8971 Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=2032604 Permissions Required
- https://bugzilla.redhat.com/show_bug.cgi?id=2479859 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2026-8971
- https://www.cve.org/CVERecord?id=CVE-2026-8971
- https://www.mozilla.org/security/advisories/mfsa2026-46/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-46/#CVE-2026-8971
- https://www.mozilla.org/security/advisories/mfsa2026-50/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-50/#CVE-2026-8971
Change history (0)
No recorded changes yet.