Sandboxie-Plus CVE-2026-34461

Requires local interactive logon access to the Windows system running Sandboxie-Plus versions 1.17.2 or earlier with the SbieSvc service active. Attacker must have low-privileged user account credentials (PR:L) capable of creating local processes and accessing named pipes. The NULL DACL on the service pipe enables any interactive process to connect without additional permissions. Attack complexity is rated HIGH (AC:H) and Attack Requirements PRESENT (AT:P), suggesting exploitation requires precise stack layout knowledge, bypass of Windows exploit mitigations (DEP, ASLR, stack cookies), or specific timing conditions for reliable code execution versus simple crash. The vulnerability is NOT exploitable remotely - local access is mandatory (AV:L). The handler's execution before sandbox checks means exploitation does not require the attacker's process to already be sandboxed. Windows-specific vulnerability; not applicable to other operating systems.

Real-world risk is MODERATE-HIGH for environments where Sandboxie-Plus is deployed and low-privileged users have local interactive access. CVSS 7.3 reflects local attack vector (AV:L) with high attack complexity (AC:H) and low privileges required (PR:L), yielding high impact across confidentiality, integrity, and availability. The AC:H and AT:P (Attack Requirements: Present) qualifiers indicate exploitation requires some skill or specific conditions, tempering the raw impact scores. No EPSS score available, and absence from CISA KEV suggests no confirmed widespread exploitation, but the GitHub Security Advisory disclosure provides sufficient technical detail for skilled attackers to develop exploits. The NULL DACL significantly lowers the exploitation barrier for local attackers. Stack buffer overflows in privileged services are high-priority targets for privilege escalation chains. Primary risk applies to multi-user Windows systems, shared workstations, or environments with untrusted local users where Sandboxie-Plus runs as a service. Single-user workstations with trusted administrators face lower risk. Key gap: no public confirmation of exploit code availability or active exploitation attempts.

A low-privileged user with local interactive access to a Windows system running vulnerable Sandboxie-Plus connects to the SbieSvc named pipe (accessible due to NULL DACL) and sends a crafted MSGID_SBIE_INI_RUN_SBIE_CTRL message containing a payload exceeding 256 bytes. The oversized payload overflows the ctrlCmd stack buffer during memcpy, overwriting return addresses or function pointers to redirect execution flow to attacker-controlled code running with SYSTEM privileges, enabling full system compromise, persistence installation, or lateral movement. GitHub Security Advisory disclosure provides implementation details sufficient for exploit development, though no public POC confirmed at time of analysis.