CVE-2026-8971
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk11th percentile - higher than 11% of all known CVEs
Summary
A same-origin policy bypass exists in the Networking: JAR component of Firefox and Thunderbird. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
Risk Assessment
An attacker can bypass the same-origin policy, potentially leading to data theft or unauthorized actions in the context of another site.
Recommendation
Update Firefox and Thunderbird to version 151 or later.
Other vulnerabilities in Firefox, Thunderbird
See all- CVE-2026-16408Critical
Integer overflow in the Audio/Video: Playback component in Firefox and Thunderbird. Fixed in versions 153.
- CVE-2026-16395Critical
Integer overflow in the Audio/Video component in Firefox and Thunderbird. Fixed in versions 153.
- CVE-2026-4729Critical
Memory safety bugs were found in Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption, which could potentially allow arbitrary code execution. The vulnerabilities were fixed in Firefox 149 and Thunderbird 149.
- CVE-2026-4720Critical
Memory safety bugs were found in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption and could potentially be exploited to run arbitrary code with enough effort.
- CVE-2026-2807Critical
Memory safety bugs were found in Firefox 147 and Thunderbird 147. Some of these bugs showed evidence of memory corruption and could potentially be exploited to run arbitrary code. The vulnerability was fixed in Firefox 148 and Thunderbird 148.
- CVE-2026-2792Critical
Memory safety bugs were found in Firefox ESR 140.7, Firefox 147, Thunderbird ESR 140.7, and Thunderbird 147. Some of these bugs showed evidence of memory corruption and could potentially be exploited to run arbitrary code with enough effort.
- CVE-2026-74978High
Clickjacking vulnerability in the Widget component in Firefox and Thunderbird. The issue was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
- CVE-2026-74977High
Integer overflow in the Graphics component in Firefox and Thunderbird. The issue was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
- CVE-2026-74965High
Privilege escalation in the Shell Integration component in Firefox and Thunderbird. The issue was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
- CVE-2026-74958High
Information disclosure in the WebRTC component in Firefox and Thunderbird. The issue was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
Original NVD description (English source)
Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS