--- title: "CVE-2025-6433\n | Ubuntu" description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/CVE-2025-6433?format=md keywords: index, follow --- # CVE-2025-6433 Publication date 24 June 2025 Last updated 26 June 2026 --- Ubuntu priority **Medium** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **9.8 · Critical** [Score breakdown](https://ubuntu.com/security/CVE-2025-6433?format=md#impact-score) Toggle side navigation ## Description If a user visited a webpage with an invalid TLS certificate, and granted an exception, the webpage was able to provide a WebAuthn challenge that the user would be prompted to complete. This is in violation of the WebAuthN spec which requires "a secure transport established without errors". This vulnerability was fixed in Firefox 140 and Thunderbird 140. [Read the notes from the security team](https://ubuntu.com/security/CVE-2025-6433?format=md#notes) ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | firefox | 26.04 LTS resolute | Not affected | | 25.10 questing | Not affected | | 25.04 plucky | Not affected | | 24.10 oracular | Not affected | | 24.04 LTS noble | Not affected | | 22.04 LTS jammy | Not affected | | mozjs102 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Ignored | | 22.04 LTS jammy | Ignored | | mozjs115 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Ignored | | 24.10 oracular | Ignored | | 24.04 LTS noble | Ignored | | 22.04 LTS jammy | Not in release | | mozjs38 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | | 18.04 LTS bionic | Needs evaluation | | mozjs52 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | | 20.04 LTS focal | Ignored | | 18.04 LTS bionic | Ignored | | mozjs68 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Not in release | | 20.04 LTS focal | Ignored | | mozjs78 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Ignored | | mozjs91 | 26.04 LTS resolute | Not in release | | 25.10 questing | Not in release | | 25.04 plucky | Not in release | | 24.10 oracular | Not in release | | 24.04 LTS noble | Not in release | | 22.04 LTS jammy | Ignored | | thunderbird | 26.04 LTS resolute | Not affected | | 25.10 questing | Not affected | | 25.04 plucky | Not affected | | 24.10 oracular | Not affected | | 24.04 LTS noble | Not affected | | 22.04 LTS jammy | Fixed 1:140.7.1+build1-0ubuntu0.22.04.1 | --- * [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) * [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses) ## Notes --- ### [mdeslaur](https://launchpad.net/~mdeslaur) mozjs\* contain a copy of the SpiderMonkey JavaScript engine. It is not feasible to backport security fixes to the mozjs\* packages, as such, marking them as ignored. starting with Ubuntu 22.04, the firefox package is just a script that installs the Firefox snap starting with Ubuntu 24.04, the thunderbird package is just a script that installs the Thunderbird snap ## Severity score breakdown CVSS version: CVSS v3.0 **Base score** 9.8 · Critical * Base metrics | Parameter | Value | | --- | --- | | Attack vector | Network | | Attack complexity | Low | | Privileges required | None | | User interaction | None | | Scope | Unchanged | | Confidentiality impact | High | | Integrity impact | High | | Availability impact | High | * Scores | Parameter | Value | | --- | --- | | Base score | 9.8 · Critical | | Exploitability score | - | | Impact score | - | **Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-6433) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2025-6433) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2025-6433) * [Debian](https://security-tracker.debian.org/tracker/CVE-2025-6433) ### Related Ubuntu Security Notices (USN) + [USN-7991-1](https://usn.ubuntu.com/USN-7991-1) + Thunderbird vulnerabilities + 2 February 2026 ### Other references * * * *