When "%2F" was present in a manifest URL, Firefox's AppCache behavior may have become confused and allowed a manifest to be served from a subdirectory. This could cause the appcache to be used to service requests for the top level directory. This vulnerability affects Firefox < 78.
78.0.1+build1-0ubuntu0.16.04.178.0.1+build1-0ubuntu0.18.04.138.8.0~repack1-0ubuntu138.8.0~repack1-0ubuntu338.8.0~repack1-0ubuntu452.3.1-0ubuntu352.3.1-7fakesync152.8.1-0ubuntu0.18.04.152.9.1-0ubuntu0.18.04.11:78.8.1+build1-0ubuntu0.18.04.178.0.1+build1-0ubuntu0.20.04.152.9.1-1build152.9.1-1ubuntu368.5.0-1~fakesync68.5.0-2~fakesync68.6.0-168.6.0-1ubuntu11:78.7.1+build1-0ubuntu0.20.04.1Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:NI:HA:NCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N