An attack can use a blob URL and script to spoof an arbitrary addressbar URL prefaced by "blob:" as the protocol, leading to user confusion and further spoofing attacks. This vulnerability affects Firefox < 52.
Severity
CVSS 3.0
5.3 medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS
12% chance of exploitation in the next 30 days; higher than 96% of CVEs (scores of 2026-10-31)