Phabricator before 2017-11-10 does not block the --config and --debugger flags to the Mercurial hg program, which allows remote attackers to execute arbitrary code by using the web UI to browse a branch whose name begins with a --config= or --debugger= substring.
Severity
CVSS 3.0
8.8 high
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
2.0% chance of exploitation in the next 30 days; higher than 80% of CVEs (scores of 2026-10-31)