CVE-2017-5397
This allows for the possibility of an installed malicious application or tools with write access to the file system to replace files used by Firefox with their own versions.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.62%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
The cache directory on the local file system is set to be world writable. Firefox defaults to extracting libraries from this cache. This allows for the possibility of an installed malicious application or tools with write access to the file system to replace files used by Firefox with their own versions. This vulnerability affects Firefox < 51.0.3.
- CVSS 3.0
- 9.8 CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 3.62% probability · 89th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-829
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
EPSS moved from 3.8% on 22 September 2026 to 3.6% on 27 October 2026.
References
- http://www.securityfocus.com/bid/96144Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1337304Issue Tracking, Patch, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-04/Vendor Advisory
- http://www.securityfocus.com/bid/96144Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1337304Issue Tracking, Patch, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-04/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.