LangGraph flaw lets dot-delimited labels bypass namespace isolation

CVE-2026-115883 (CVSS 6.0) in LangGraph's PostgreSQL and SQLite stores lets an attacker use a namespace label containing a period to cross namespace boundaries and read, search or delete other tenants' data. Only write operations validated labels before the fix. Patched in langgraph 1.2.15, langgraph-checkpoint 4.3.0, langgraph-checkpoint-postgres 3.1.3 and langgraph-checkpoint-sqlite 3.1.2.

• CVSS 6.0 authorization bypass affects read, search and delete operations
• A label like ('foo.bar',) collides with ('foo', 'bar') and breaks isolation
• Fixes: langgraph 1.2.15 and langgraph-checkpoint 4.3.0
• PoC included in regression tests from PR #9217; not in CISA KEV