CVE-2025-6424

Use-after-free in FontFaceSet

A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.

CVSS 3.1 · 9.8 Critical EPSS 7.9% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Firefox Esr Enterprise Linux and 5 more

CVE-2025-6429

Incorrect parsing of URLs could have allowed embedding of youtube.com

Firefox could have incorrectly parsed a URL and rewritten it to the youtube.com domain when parsing the URL specified in an `embed` tag. This could have bypassed website security checks that restricted which domains users were allowed to embed. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Firefox Esr Enterprise Linux and 5 more

CVE-2025-0237

WebChannel APIs susceptible to confused deputy attack

The WebChannel API, which is used to transport various information across processes, did not check the sending principal but rather accepted the principal being sent. This could have led to privilege escalation attacks. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.

CVSS 3.1 · 5.4 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-0238

Use-after-free when breaking lines in text

Assuming a controlled failed memory allocation, an attacker could have caused a use-after-free, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Firefox ESR 115.19, Thunderbird 134, and Thunderbird 128.6.

CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-0240

Compartment mismatch when parsing JavaScript JSON module

Parsing a JavaScript module as JSON could, under some circumstances, cause cross-compartment access, which may result in a use-after-free. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.

CVSS 3.1 · 4 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-0243

Memory safety bugs fixed in Firefox 134, Thunderbird 134, Firefox ESR 128.6, and Thunderbird 128.6

Memory safety bugs present in Firefox 133, Thunderbird 133, Firefox ESR 128.5, and Thunderbird 128.5. 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 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.

CVSS 3.1 · 5.1 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-1009

Use-after-free in XSLT

An attacker could have caused a use-after-free via crafted XSLT data, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

CVSS 3.1 · 9.8 Critical EPSS 1.2% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-1011

A bug in WebAssembly code generation could result in a crash

A bug in WebAssembly code generation could have lead to a crash. It may have been possible for an attacker to leverage this to achieve code execution. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-1013

Potential opening of private browsing tabs in normal browsing windows

A race condition could have led to private browsing tabs being opened in normal browsing windows. This could have resulted in a potential privacy leak. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-1014

Certificate length was not properly checked

Certificate length was not properly checked when added to a certificate store. In practice only trusted data was processed. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-1016

Memory safety bugs fixed in Firefox 135, Thunderbird 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 115.20, and Thunderbird 128.7

Memory safety bugs present in Firefox 134, Thunderbird 134, Firefox ESR 115.19, Firefox ESR 128.6, Thunderbird 115.19, and Thunderbird 128.6. 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 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-1015

Unsanitized address book fields

The Thunderbird Address Book URI fields contained unsanitized links. This could be used by an attacker to create and export an address book containing a malicious payload in a field. For example, in the “Other” field of the Instant Messaging section. If another user imported the address book, clicking on the link could result in opening a web page inside Thunderbird, and that page could execute (unprivileged) JavaScript. This vulnerability was fixed in Thunderbird 128.7 and Thunderbird 135.

CVSS 3.1 · 5.4 Medium EPSS 1.4% KEV · Not listed

Vendors

Mozilla Redhat

Products

Thunderbird Enterprise Linux Rhel Aus and 3 more

CVE-2025-1936

Adding %00 and a fake extension to a jar: URL changed the interpretation of the contents

jar: URLs retrieve local file content packaged in a ZIP archive. The null and everything after it was ignored when retrieving the content from the archive, but the fake extension after the null was used to determine the type of content. This could have been used to hide code in a web extension disguised as something else like an image. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

CVSS 3.1 · 7.3 High EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-1938

Memory safety bugs fixed in Firefox 136, Thunderbird 136, Firefox ESR 128.8, and Thunderbird 128.8

Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7. 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 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-3028

Use-after-free triggered by XSLTProcessor

JavaScript code running while transforming a document with the XSLTProcessor could lead to a use-after-free. This vulnerability was fixed in Firefox 137, Firefox ESR 115.22, Firefox ESR 128.9, Thunderbird 137, and Thunderbird 128.9.

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-3030

Memory safety bugs fixed in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9

Memory safety bugs present in Firefox 136, Thunderbird 136, Firefox ESR 128.8, and Thunderbird 128.8. 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 137, Firefox ESR 128.9, Thunderbird 137, and Thunderbird 128.9.

CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more

CVE-2025-2830

Information Disclosure of /tmp directory listing

By crafting a malformed file name for an attachment in a multipart message, an attacker can trick Thunderbird into including a directory listing of /tmp when the message is forwarded or edited as a new message. This vulnerability could allow attackers to disclose sensitive information from the victim's system. This vulnerability is not limited to Linux; similar behavior has been observed on Windows as well. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.

CVSS 3.1 · 6.3 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Thunderbird Enterprise Linux Rhel Aus and 3 more

CVE-2025-6425

The WebCompat WebExtension shipped with Firefox exposed a persistent UUID

An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Firefox Esr Enterprise Linux and 5 more

CVE-2025-3523

User Interface (UI) Misrepresentation of attachment URL

When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL header, only the last link is shown when hovering over any attachment. Although the correct link is used on click, the misleading hover text could trick users into downloading content from untrusted sources. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.

CVSS 3.1 · 6.4 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Thunderbird Enterprise Linux Rhel Aus and 3 more

CVE-2025-4083

Process isolation bypass using "javascript:" URI links in cross-origin frames

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 Thunderbird 128.10.

CVSS 3.1 · 9.1 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla Redhat

Products

Firefox Thunderbird Enterprise Linux and 5 more