CVE-2018-5135
WebExtensions can bypass normal restrictions in some circumstances and use "browser.tabs.executeScript" to inject scripts into contexts where this should not be allowed, such as pages from other WebExtensions or unprivileged "about:" pages.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.50%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
WebExtensions can bypass normal restrictions in some circumstances and use "browser.tabs.executeScript" to inject scripts into contexts where this should not be allowed, such as pages from other WebExtensions or unprivileged "about:" pages. This vulnerability affects Firefox < 59.
- CVSS 3.0
- 7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- EPSS
- 1.50% probability · 74th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-862
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
EPSS 1.5% 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/103386Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1040514Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1431371Permissions Required
- https://usn.ubuntu.com/3596-1/Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-06/Vendor Advisory
- http://www.securityfocus.com/bid/103386Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1040514Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1431371Permissions Required
- https://usn.ubuntu.com/3596-1/Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-06/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.