What is CVE-2025-5986?

CVE-2025-5986 is a medium-severity vulnerability in Mozilla Thunderbird, classified under User Interface (UI) Misrepresentation of Critical Information. CVSS score: 6.5/10. Published 2025-06-11.

How severe is CVE-2025-5986?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Is CVE-2025-5986 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Mozilla Thunderbird

CVE-2025-5986

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 dis…

EPSS: 0.005 (36.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

Affected products

Mozilla Thunderbird — versions 128.11.1, 139.0.2

Weakness classification (CWE)

CWE-451 — User Interface (UI) Misrepresentation of Critical Information

Public proof-of-concept exploits

ARPSyndicate/cve-scores

References

Frequently asked questions

What is CVE-2025-5986?: CVE-2025-5986 is a medium-severity vulnerability in Mozilla Thunderbird, classified under User Interface (UI) Misrepresentation of Critical Information. CVSS score: 6.5/10. Published 2025-06-11.
How severe is CVE-2025-5986?: Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2025-5986 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.