{"items":[{"id":"NVI-00008987","kind":"vulnerability","title":"Strands Agents: Local Privilege Escalation via Symlink Attack in Default Session File Storage","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-3w55-933p-8pv5"],"plain_summary":"GitHub lists this reviewed advisory for strands-agents. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-624285b1a5ceca46e72f97b6ec2f03ef"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-10-27T15:34:33.000Z","value":"7.1 high","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-624285b1a5ceca46e72f97b6ec2f03ef"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-624285b1a5ceca46e72f97b6ec2f03ef","url":"https://github.com/advisories/GHSA-3w55-933p-8pv5","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-3w55-933p-8pv5","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T21:56:51.534Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-624285b1a5ceca46e72f97b6ec2f03ef"],"technology":"strands-agents","known_exclusions":[],"conditions_summary":"## Summary\n\nThe `FileSessionManager` defaults to storing session data in `/tmp/strands/sessions/` (a world-writable directory) using predictable file paths and a write pattern (`open(path + \".tmp\", \"w\")` → `os.replace()`) that follows symbolic links. A local attacker can exploit this to overwrite arbitrary files or inject malicious session data for persistent prompt injection.\n\n## Vulnerability Details\n\n**Component:** `strands-py/src/strands/session/file_session_manager.py`\n\n**Root Cause:**\n1. Default storage directory is `tempfile.gettempdir() + \"/strands/sessions/\"` (line 58) — resolves to `/tmp/strands/sessions/` on Linux/macOS\n2. The `_write_file()` method (lines 116-123) writes to a predictable `.tmp` path without symlink protection:\n   ```python\n   tmp = f\"{path}.tmp\"\n   with open(tmp, \"w\", encoding=\"utf-8\", newline=\"\\n\") as f:\n       json.dump(data, f, indent=2, ensure_ascii=False)\n   os.replace(tmp, path)\n   ```\n3. `open()` follows symlinks — a pre-placed symlink at the `.tmp` path causes writes to an arbitrary target file\n4. No integrity verification (HMAC/signature) on session files — tampered data is loaded as-is\n\n## Attack Vectors\n\n### 1. Arbitrary File Overwrite (Local","public_affected_ranges":["< 1.48.0"]}],"null_published_at":"2026-10-31T22:13:27.126Z","source_updated_at":"2026-10-27T15:34:33.000Z","source_disclosed_at":"2026-10-27T15:34:33.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-10-31T21:56:51.534Z"}],"next_cursor":null,"snapshot_revision":"42594"}