Bastille EUVD-2026-114109

The attacker must already have a shell or account inside a Bastille jail (PR:L) with write access to the jail filesystem so they can plant symlinks pointing outside the jail root. Exploitation additionally depends on a host administrator subsequently invoking the cp.sh, rcp.sh or jcp.sh subcommand against the affected jail (UI:P) - the root-privileged copy only follows the planted symlink when that operator action occurs, so the flaw cannot be triggered by the jailed user alone. It is not remotely reachable (AV:L) and is limited to Bastille versions through 1.4.4; the only complete fix stated by the evidence is the vendor patch that resolves symlinks and refuses copies resolving outside the jail root.

This is a medium-severity local privilege/isolation flaw, not a remote emergency. The CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:L/UI:P) shows the attacker must already hold a foothold inside a Bastille jail (PR:L) and cannot act alone: UI:P means exploitation is gated on a host administrator later running the cp/rcp/jcp subcommand, which is the real-world throttle on this bug. Impact is meaningful once triggered - integrity and availability are high (VI:H/VA:H: root-run copies overwrite host files) with lower confidentiality (VC:L: reading host files), amounting to a jail-escape primitive. Decision signals are consistent and point to measured urgency, not panic: the vuln.today priority is 'this_month' (not act_now/emergency), there is no CISA KEV listing, no EPSS score was provided, and no confirmed working exploit was supplied - only a VulnCheck advisory and a GitHub issue reference. The main caveat is that the supplied CVSS 4.0 vector sets subsequent-system metrics to none (SC:N/SI:N/SA:N) even though the described effect is precisely a jail-to-host escape; a jail escape arguably crosses a security boundary, so the host impact may be understated relative to a strict scope/subsequent-system reading. Net: a genuine issue worth patching on a normal cycle, but its need for an existing jail account plus an administrator-initiated copy keeps real-world risk below what the 'jail escape as root' phrasing might suggest.

A user confined to a Bastille jail writes a symlink inside the jail filesystem pointing at a host path or another jail's root. When the host administrator subsequently runs 'bastille cp', 'bastille rcp', or 'bastille jcp' involving that jail, the root-privileged copy follows the symlink and reads or overwrites files outside the jail root. No confirmed working exploit was supplied; a VulnCheck advisory and a GitHub issue (#1673) describe the flaw.