CVE-2025-5986
6.5 · MEDIUMOverview
CVE-2025-5986 is a medium-severity vulnerability affecting mozilla thunderbird. It was published on June 11, 2025 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
A crafted HTML email using mailbox:/// links can trigger automatic, unsolicited downloads of .pdf files to the user's desktop or home directory without prompting, even if auto-saving is disabled. This behavior can be abused to fill the disk with garbage data (e.g. using /dev/urandom on Linux) or to leak Windows credentials via SMB links when the email is viewed in HTML mode. While user interaction is required to download the .pdf file, visual obfuscation can conceal the download trigger. Viewing the email in HTML mode is enough to load external content. This vulnerability was fixed in Thunderbird 128.11.1 and Thunderbird 139.0.2.
Remediation
Check the references section for vendor advisories and patches from mozilla. Update thunderbird to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| mozilla | thunderbird | >= 0, < 128.11.1 | Affected |
Frequently Asked Questions
What is CVE-2025-5986?
CVE-2025-5986 is a medium-severity vulnerability affecting mozilla thunderbird. It was published on June 11, 2025 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
How severe is CVE-2025-5986?
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2025-5986?
Check the references section for vendor advisories and patches from mozilla. Update thunderbird to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-5986?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-5986 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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