---
id: GHSA-763v-5pjm-fx36
title: >-
  Strands Agents: Default FileSessionManager storage is world-readable on shared
  systems
summary: >-
  Strands Agents: Default FileSessionManager storage is world-readable on shared
  systems
severity: medium
vendor: strands-agents
product: strands-agents
ecosystem: pip
affected:
  - strands-agents < 1.48.0
patched:
  - strands-agents 1.48.0
published: '2026-10-27'
updated: '2026-10-27'
sourceUpdated: '2026-10-27T15:47:24.152066847Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-763v-5pjm-fx36'
references:
  - url: >-
      https://github.com/strands-agents/harness-sdk/security/advisories/GHSA-763v-5pjm-fx36
  - url: 'https://github.com/strands-agents/harness-sdk/pull/2937'
  - url: >-
      https://github.com/strands-agents/harness-sdk/commit/8658b9e0d57427b77b69343262184d76d8e63e8f
  - url: 'https://github.com/strands-agents/harness-sdk'
  - url: 'https://github.com/strands-agents/harness-sdk/releases/tag/python/v1.48.0'
  - url: 'https://github.com/advisories/GHSA-763v-5pjm-fx36'
tags:
  - osv
  - pip
  - ghsa
cwe:
  - CWE-276
ingestedAt: '2026-10-27T16:11:58.711Z'
---

## Overview

There is a local confidentiality issue in the default `FileSessionManager` storage behavior. By default it writes session data under `/tmp/strands/sessions` and relies on the process umask for directory and file permissions. On systems using the common `umask 022`, the session directories are `0755` and JSON files are `0644`, so other local users can read persisted agent session data.

This matters on shared developer machines, CI hosts, notebooks, jump boxes, and multi-user GPU servers. Session storage is intended to persist conversation/history/state, so it can contain prompts, model output, tool inputs/outputs, intermediate state, and secrets that pass through the agent.

Relevant code:
- `strands-py/src/strands/session/file_session_manager.py:58`: default storage path is `os.path.join(tempfile.gettempdir(), "strands/sessions")`.
- `strands-py/src/strands/session/file_session_manager.py:118`: creates parent directories without a private mode.
- `strands-py/src/strands/session/file_session_manager.py:121`: writes JSON files via normal `open(..., "w")`.
- `strands-py/src/strands/session/file_session_manager.py:131`: creates session directories without a private mode.

Local reproduction with `umask 022`:

```text
default_storage_dir= /tmp/strands/sessions
0o755 /tmp/strands/sessions
0o755 /tmp/strands/sessions/session_codex_perm_poc
0o644 /tmp/strands/sessions/session_codex_perm_poc/session.json
file_contains_secret= True
```

The fixture wrote a fake secret into the session dict to show that sensitive session fields are readable through the resulting file.

Suggested fixes:
- Use a private per-user data directory by default rather than `/tmp`, or create `/tmp/strands` and descendants with `0700`.
- Write session JSON atomically with `0600` permissions.
- Consider refusing to use an existing default storage directory if it is not owned by the current user or is group/world accessible.
- Document that callers should set `storage_dir` explicitly when they need shared storage.

This was reproduced on commit `dd7b41de38cb`.

## Affected packages

- `strands-agents < 1.48.0`

## Remediation

Upgrade to a patched release:

- `strands-agents 1.48.0`