CVE-2018-5166
WebExtensions can use request redirection and a "filterReponseData" filter to bypass host permission settings to redirect network traffic and access content from a host for which they do not have explicit user permission.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (2.35%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
WebExtensions can use request redirection and a "filterReponseData" filter to bypass host permission settings to redirect network traffic and access content from a host for which they do not have explicit user permission. This vulnerability affects Firefox < 60.
- CVSS 3.0
- 7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 2.35% probability · 84th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-269
- Affected
- canonical/ubuntu linux · mozilla/firefox
- Source
- security@mozilla.org
EPSS 2.4% 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/104139Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1040896Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1437325Issue Tracking, Permissions Required, Vendor Advisory
- https://usn.ubuntu.com/3645-1/Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-11/Vendor Advisory
- http://www.securityfocus.com/bid/104139Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1040896Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1437325Issue Tracking, Permissions Required, Vendor Advisory
- https://usn.ubuntu.com/3645-1/Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-11/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.