The executable file warning was not presented when downloading .xrm-ms files. *Note: This issue only affected Windows operating systems.…

Description

The executable file warning was not presented when downloading .xrm-ms files. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.* This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

Scores

EPSS (exploitation in 30 days)

0.81% · top 43% of all CVEs (7 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.

Weakness

• Download Protections were bypassed by .xrm-ms files on Windows
• CWE-434 Unrestricted Upload of File with Dangerous Type (opens in a new tab)All about CWE-434 and its CVEs

Affected products

• Mozilla · Firefox

  • affected unspecified – < 125

• Mozilla · Firefox ESR

  • affected unspecified – < 115.10

• Mozilla · Thunderbird

  • affected unspecified – < 115.10

References (4)

• https://bugzilla.mozilla.org/show_bug.cgi?id=1885855 (opens in a new tab)x_transferred
• https://www.mozilla.org/security/advisories/mfsa2024-18/ (opens in a new tab)x_transferred
• https://www.mozilla.org/security/advisories/mfsa2024-19/ (opens in a new tab)x_transferred
• https://www.mozilla.org/security/advisories/mfsa2024-20/ (opens in a new tab)x_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2024-3863](https://trackcve.app/badge/CVE-2024-3863.svg)](https://trackcve.app/cve/CVE-2024-3863)

Record last updated 4 Nov 2026, 00:01 UTC.