CVE-2018-5116
Malicious extensions can inject frames from arbitrary origins into the loaded page and then interact with them, bypassing same-origin user expectations with this permission.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.14%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
WebExtensions with the "ActiveTab" permission are able to access frames hosted within the active tab even if the frames are cross-origin. Malicious extensions can inject frames from arbitrary origins into the loaded page and then interact with them, bypassing same-origin user expectations with this permission. This vulnerability affects Firefox < 58.
- 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
- 1.14% probability · 67th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-346
- Affected
- mozilla/firefox · canonical/ubuntu linux
- Source
- security@mozilla.org
EPSS 1.1% 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/102786Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1040270Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1396399Issue Tracking, Permissions Required
- https://usn.ubuntu.com/3544-1/Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-02/Vendor Advisory
- http://www.securityfocus.com/bid/102786Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1040270Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1396399Issue Tracking, Permissions Required
- https://usn.ubuntu.com/3544-1/Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-02/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.