CVE-2017-7755
The Firefox installer on Windows can be made to load malicious DLL files stored in the same directory as the installer when it is run.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.36%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
The Firefox installer on Windows can be made to load malicious DLL files stored in the same directory as the installer when it is run. This allows privileged execution if the installer is run with elevated privileges. Note: This attack only affects Windows operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 54, Firefox ESR < 52.2, and Thunderbird < 52.2.
- CVSS 3.0
- 7.8 HIGHCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 1.36% probability · 72th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-426
- Affected
- mozilla/firefox · mozilla/thunderbird
- Source
- security@mozilla.org
EPSS 1.4% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.securityfocus.com/bid/99057Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1038689Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1361326Issue Tracking, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-15/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-16/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-17/Vendor Advisory
- http://www.securityfocus.com/bid/99057Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1038689Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1361326Issue Tracking, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-15/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-16/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-17/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.