What happened
CVE-2026-75110 (CVSS 9.8 Critical), published 2026-08-17, describes a fail-open authentication bypass in MemOS caused by an undocumented environment variable with no default value; if operators are unaware of the variable and never set it, the internal-request check silently trusts any request as internal.
Why it matters
MemOS provides persistent memory for LLM agents; bypassing its authentication grants full unauthenticated access to an agent's stored memories and internal APIs, which can include sensitive conversation history, credentials, or context used to steer agent behavior.
Attack vector
In deployments with AUTH_ENABLED=true but the undocumented, defaultless INTERNAL_SERVICE_SECRET environment variable left unset, the is_internal_request() check in src/memos/api/middleware/auth.py fails open, treating unauthenticated requests as trusted internal service calls and bypassing authentication entirely.
Affected systems
MemOS (memory operating system for LLMs and AI agents), MemTensor/MemOS
Mitigation
Explicitly set INTERNAL_SERVICE_SECRET in all MemOS deployments; audit deployment configs for this undocumented variable; upgrade to the patched release per MemTensor's advisory.