CVE-2018-5136
A shared worker created from a "data:" URL in one tab can be shared by another tab with a different origin, bypassing the same-origin policy.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.59%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
A shared worker created from a "data:" URL in one tab can be shared by another tab with a different origin, bypassing the same-origin policy. This vulnerability affects Firefox < 59.
- 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
- 1.59% probability · 76th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-20
- Affected
- canonical/ubuntu linux · mozilla/firefox
- Source
- security@mozilla.org
EPSS 1.6% 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=1419166Issue Tracking, Permissions 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=1419166Issue Tracking, Permissions 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.