Mozilla Firefox vulnerabilities

CVE-2025-5263 [MEDIUM] CWE-346 CVE-2025-5263: Error handling for script execution was incorrectly isolated from web content, which could have allo Error handling for script execution was incorrectly isolated from web content, which could have allowed cross-origin leak attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 115.24, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

CVE-2025-5271 [MEDIUM] CWE-116 CVE-2025-5271: Previewing a response in Devtools ignored CSP headers, which could have allowed content injection at Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139.

CVE-2025-5264 [MEDIUM] CWE-77 CVE-2025-5264: Due to insufficient escaping of the newline character in the “Copy as cURL” feature, an attacker cou Due to insufficient escaping of the newline character in the “Copy as cURL” feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. This vulnerability was fixed in Firefox 139, Firefox ESR 115.24, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

CVE-2025-5266 [MEDIUM] CWE-200 CVE-2025-5266: Script elements loading cross-origin resources generated load and error events which leaked informat Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

CVE-2025-5267 [MEDIUM] CWE-1021 CVE-2025-5267: A clickjacking vulnerability could have been used to trick a user into leaking saved payment card de A clickjacking vulnerability could have been used to trick a user into leaking saved payment card details to a malicious page. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

CVE-2025-5020 [MEDIUM] CWE-939 CVE-2025-5020: Opening maliciously-crafted URLs in Firefox from other apps such as Safari could have allowed attack Opening maliciously-crafted URLs in Firefox from other apps such as Safari could have allowed attackers to spoof website addresses if the URLs utilized non-HTTP schemes used internally by the Firefox iOS client. This vulnerability was fixed in Firefox for iOS 139.

CVE-2025-4918 [CRITICAL] CWE-125 CVE-2025-4918: An attacker was able to perform an out-of-bounds read or write on a JavaScript `Promise` object. Thi An attacker was able to perform an out-of-bounds read or write on a JavaScript `Promise` object. This vulnerability was fixed in Firefox 138.0.4, Firefox ESR 128.10.1, Firefox ESR 115.23.1, Thunderbird 128.10.2, and Thunderbird 138.0.2.

CVE-2025-4919 [HIGH] CWE-125 CVE-2025-4919: An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing a An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes. This vulnerability was fixed in Firefox 138.0.4, Firefox ESR 128.10.1, Firefox ESR 115.23.1, Thunderbird 128.10.2, and Thunderbird 138.0.2.

CVE-2025-4083 [CRITICAL] CWE-653 CVE-2025-4083: A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and T

CVE-2025-4091 [HIGH] CWE-119 CVE-2025-4091: Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9 Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Thunderbird 138, and Thunderbi

CVE-2025-4093 [HIGH] CWE-119 CVE-2025-4093: Memory safety bug present in Firefox ESR 128.9, and Thunderbird 128.9. This bug showed evidence of m Memory safety bug present in Firefox ESR 128.9, and Thunderbird 128.9. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox ESR 128.10 and Thunderbird 128.10.

CVE-2025-4085 [HIGH] CWE-269 CVE-2025-4085: An attacker with control over a content process could potentially leverage the privileged UITour act An attacker with control over a content process could potentially leverage the privileged UITour actor to leak sensitive information or escalate privileges. This vulnerability was fixed in Firefox 138 and Thunderbird 138.

CVE-2025-2817 [HIGH] CWE-22 CVE-2025-2817: Thunderbird's update mechanism allowed a medium-integrity user process to interfere with the SYSTEM- Thunderbird's update mechanism allowed a medium-integrity user process to interfere with the SYSTEM-level updater by manipulating the file-locking behavior. By injecting code into the user-privileged process, an attacker could bypass intended access controls, allowing SYSTEM-level file operations on paths controlled by a non-privileged user and enabling

CVE-2025-4082 [MEDIUM] CWE-125 CVE-2025-4082: Modification of specific WebGL shader attributes could trigger an out-of-bounds read, which, when ch Modification of specific WebGL shader attributes could trigger an out-of-bounds read, which, when chained with other vulnerabilities, could be used to escalate privileges. *This bug only affects Thunderbird for macOS. Other versions of Thunderbird are unaffected.*. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Th

CVE-2025-4088 [MEDIUM] CWE-352 CVE-2025-4088: A security vulnerability in Thunderbird allowed malicious sites to use redirects to send credentiale A security vulnerability in Thunderbird allowed malicious sites to use redirects to send credentialed requests to arbitrary endpoints on any site that had invoked the Storage Access API. This enabled potential Cross-Site Request Forgery attacks across origins. This vulnerability was fixed in Firefox 138 and Thunderbird 138.

CVE-2025-4092 [MEDIUM] CWE-119 CVE-2025-4092: Memory safety bugs present in Firefox 137 and Thunderbird 137. Some of these bugs showed evidence of Memory safety bugs present in Firefox 137 and Thunderbird 137. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 138 and Thunderbird 138.

CVE-2025-4087 [MEDIUM] CWE-125 CVE-2025-4087: A vulnerability was identified in Thunderbird where XPath parsing could trigger undefined behavior d A vulnerability was identified in Thunderbird where XPath parsing could trigger undefined behavior due to missing null checks during attribute access. This could lead to out-of-bounds read access and potentially, memory corruption. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Thunderbird 138, and Thunderbird 128.10.

CVE-2025-4089 [MEDIUM] CWE-77 CVE-2025-4089: Due to insufficient escaping of special characters in the "copy as cURL" feature, an attacker could Due to insufficient escaping of special characters in the "copy as cURL" feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. This vulnerability was fixed in Firefox 138 and Thunderbird 138.

CVE-2025-4086 [MEDIUM] CWE-451 CVE-2025-4086: A specially crafted filename containing a large number of encoded newline characters could obscure t A specially crafted filename containing a large number of encoded newline characters could obscure the file's extension when displayed in the download dialog. *This bug only affects Thunderbird for Android. Other versions of Thunderbird are unaffected.*. This vulnerability was fixed in Firefox 138 and Thunderbird 138.

CVE-2025-4090 [MEDIUM] CWE-532 CVE-2025-4090: A vulnerability existed in Thunderbird for Android where potentially sensitive library locations wer A vulnerability existed in Thunderbird for Android where potentially sensitive library locations were logged via Logcat. This vulnerability was fixed in Firefox 138 and Thunderbird 138.