Vulnerability-Lookup

CVE-2026-87997 (GCVE-0-2026-87997)

Vulnerability from cvelistv5 – Published: 2026-09-09 21:30 – Updated: 2026-09-14 13:44

Title

Open WebUI: Any authenticated user can inject chats into another user's folder via chat completions

Summary

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.10.0 until 0.11.1, POST /api/chat/completions and POST /api/v1/chat/completions in backend/open_webui/main.py copied a client-supplied folder_id into a new chat without applying the folder write-access check used by the dedicated chat routes. An authenticated user who knew a shared folder identifier could inject an attacker-controlled chat into a folder where the user had read-only or no write access, causing the entry to appear to authorized folder readers. This issue is fixed in version 0.11.1.

Severity

4.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-14 13:43 UTC

CWE

CWE-639 - Authorization Bypass Through User-Controlled Key
CWE-862 - Missing Authorization

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/open-webui/open-webui/security…	x_refsource_CONFIRM
https://github.com/open-webui/open-webui/pull/28366	x_refsource_MISC
https://github.com/open-webui/open-webui/commit/d…	x_refsource_MISC
https://github.com/open-webui/open-webui/releases…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
open-webui	open-webui	Affected: >= 0.10.0, < 0.11.1	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-87997

Vulnerability from fkie_nvd - Published: 2026-09-09 22:18 - Updated: 2026-09-16 15:14

Severity

4.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Summary

References

URL	Tags
security-advisories@github.com	https://github.com/open-webui/open-webui/commit/d9e23b90c100d19b00270aea3cde0501d2354a6c	Patch
security-advisories@github.com	https://github.com/open-webui/open-webui/pull/28366	Issue Tracking, Patch
security-advisories@github.com	https://github.com/open-webui/open-webui/releases/tag/v0.11.1	Release Notes
security-advisories@github.com	https://github.com/open-webui/open-webui/security/advisories/GHSA-3pf7-q2g3-wj28	Exploit, Vendor Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/open-webui/open-webui/security/advisories/GHSA-3pf7-q2g3-wj28	Exploit, Vendor Advisory

Impacted products

	Vendor	Product	Version
	openwebui	open_webui	*

JSON

To clipboard

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        {
          "lang": "en",
          "value": "CWE-862"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-3PF7-Q2G3-WJ28

Vulnerability from github – Published: 2026-09-10 15:10 – Updated: 2026-09-10 15:10

Summary

Open WebUI: Any authenticated user can inject chats into another user's folder via chat completions

Details

Summary

The chat-completions endpoint reads a folder id out of the request body and saves the newly created chat into that folder without checking that the caller is allowed to write there. Any authenticated user who knows a folder's id can put a chat of their own into another user's folder, including a shared folder where they hold read-only access and a folder they have no access to at all. The chat then shows up in that folder for everyone who can read it, under a title and with content the attacker controls. The dedicated chat-creation and chat-move endpoints already enforced this check, the chat-completions path did not.

Preconditions

An authenticated account of any role. No elevated permission, no admin involvement.
Folders enabled, which is the default (ENABLE_FOLDERS=true, USER_PERMISSIONS_FEATURES_FOLDERS=true).
The attacker needs the target folder's id. A member of a shared folder gets it from the shared-folder listing. Sharing a folder with named users is available to ordinary users by default; only wildcard public sharing is gated. A folder that was never shared has an id the attacker cannot obtain through any endpoint available to them, so those folders are not practically reachable.
Releases before 0.10.0 contain the same missing check but have no read path that lists a folder's chats across owners, so the injected row was never visible to anyone.

Impact

The integrity of folder contents. An attacker who cannot write to a folder can place chats into it, and every member with read access, the owner included, sees the entry with the attacker's display name and a title the attacker can change to arbitrary text at any time. Members can also open the injected chat and read its messages. In a workspace where a shared folder is treated as trusted, that is a usable surface for planting misleading or phishing content under another team's nose.

Nothing is disclosed to the attacker and nothing existing is altered. Writing into a folder grants no read access to it, so the attacker still cannot list or open the folder's other chats, and no data belonging to other users can be modified or deleted through this path. Availability is unaffected.

Fix

Fixed in 0.11.1 by https://github.com/open-webui/open-webui/pull/28366. Chat creation, chat moves and the chat-completions creation path now share a single folder write-access check, so a folder id the caller cannot write to is rejected everywhere a chat's folder can be set. Upgrading to 0.11.1 resolves it completely, with no configuration change required.

Root cause

Affected component: the chat-completions handler in backend/open_webui/main.py, reached through POST /api/chat/completions and POST /api/v1/chat/completions. Affected setup: every deployment on 0.10.0 through 0.11.0 with folders enabled.

The completions handler gained its own chat-creation branch, which copied the client-supplied folder id into the chat it saved. The ownership and shared-write check lived as duplicated inline code inside the two chat routers rather than in one shared helper, so a third place that learned to set a folder id inherited none of it. Separately, folder listings had been changed to return a folder's chats across all owners so that shared folders work at all, which turned a write that used to be invisible to everyone into one the whole folder can see.

Proof of concept

Reproduced on a running instance at 0.11.0 with three accounts: one administrator and two ordinary users, one acting as victim and one as attacker.

The victim creates a folder. The attacker is given no access to it: reading the folder returns 404 and listing its chats returns 403.
The attacker sends POST /api/v1/chats/new with the victim's folder id. Rejected with 404, which is the pre-existing guard working.
The attacker sends POST /api/chat/completions with parent_id: null, no chat id, and the victim's folder id in the body. Accepted.
The victim lists their own folder and sees a chat owned by "Attacker". The victim can open it and read its messages. The attacker then renames their own chat and the new title appears verbatim in the victim's folder listing.

Repeating step 3 with the attacker granted read-only access to a shared folder also succeeds on 0.11.0. On 0.11.1 both variants are rejected with 404 and the folder stays empty, while a member holding write access can still create chats there as intended.

The three accounts and the folder were created through the normal API. Nothing was written directly to the database.

Credits

whyiug, for reporting the missing folder write-access check on the chat-completions creation path.

Severity

4.3 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.10.0"
            },
            {
              "fixed": "0.11.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-87997"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-639",
      "CWE-862"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-10T15:10:04Z",
    "nvd_published_at": "2026-09-09T22:18:48Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\nThe chat-completions endpoint reads a folder id out of the request body and saves the newly created chat into that folder without checking that the caller is allowed to write there. Any authenticated user who knows a folder\u0027s id can put a chat of their own into another user\u0027s folder, including a shared folder where they hold read-only access and a folder they have no access to at all. The chat then shows up in that folder for everyone who can read it, under a title and with content the attacker controls. The dedicated chat-creation and chat-move endpoints already enforced this check, the chat-completions path did not.\n\n## Preconditions\n- An authenticated account of any role. No elevated permission, no admin involvement.\n- Folders enabled, which is the default (`ENABLE_FOLDERS=true`, `USER_PERMISSIONS_FEATURES_FOLDERS=true`).\n- The attacker needs the target folder\u0027s id. A member of a shared folder gets it from the shared-folder listing. Sharing a folder with named users is available to ordinary users by default; only wildcard public sharing is gated. A folder that was never shared has an id the attacker cannot obtain through any endpoint available to them, so those folders are not practically reachable.\n- Releases before 0.10.0 contain the same missing check but have no read path that lists a folder\u0027s chats across owners, so the injected row was never visible to anyone.\n\n## Impact\nThe integrity of folder contents. An attacker who cannot write to a folder can place chats into it, and every member with read access, the owner included, sees the entry with the attacker\u0027s display name and a title the attacker can change to arbitrary text at any time. Members can also open the injected chat and read its messages. In a workspace where a shared folder is treated as trusted, that is a usable surface for planting misleading or phishing content under another team\u0027s nose.\n\nNothing is disclosed to the attacker and nothing existing is altered. Writing into a folder grants no read access to it, so the attacker still cannot list or open the folder\u0027s other chats, and no data belonging to other users can be modified or deleted through this path. Availability is unaffected.\n\n## Fix\nFixed in 0.11.1 by https://github.com/open-webui/open-webui/pull/28366. Chat creation, chat moves and the chat-completions creation path now share a single folder write-access check, so a folder id the caller cannot write to is rejected everywhere a chat\u0027s folder can be set. Upgrading to 0.11.1 resolves it completely, with no configuration change required.\n\n## Root cause\nAffected component: the chat-completions handler in `backend/open_webui/main.py`, reached through `POST /api/chat/completions` and `POST /api/v1/chat/completions`. Affected setup: every deployment on 0.10.0 through 0.11.0 with folders enabled.\n\nThe completions handler gained its own chat-creation branch, which copied the client-supplied folder id into the chat it saved. The ownership and shared-write check lived as duplicated inline code inside the two chat routers rather than in one shared helper, so a third place that learned to set a folder id inherited none of it. Separately, folder listings had been changed to return a folder\u0027s chats across all owners so that shared folders work at all, which turned a write that used to be invisible to everyone into one the whole folder can see.\n\n## Proof of concept\nReproduced on a running instance at 0.11.0 with three accounts: one administrator and two ordinary users, one acting as victim and one as attacker.\n\n1. The victim creates a folder. The attacker is given no access to it: reading the folder returns 404 and listing its chats returns 403.\n2. The attacker sends `POST /api/v1/chats/new` with the victim\u0027s folder id. Rejected with 404, which is the pre-existing guard working.\n3. The attacker sends `POST /api/chat/completions` with `parent_id: null`, no chat id, and the victim\u0027s folder id in the body. Accepted.\n4. The victim lists their own folder and sees a chat owned by \"Attacker\". The victim can open it and read its messages. The attacker then renames their own chat and the new title appears verbatim in the victim\u0027s folder listing.\n\nRepeating step 3 with the attacker granted read-only access to a shared folder also succeeds on 0.11.0. On 0.11.1 both variants are rejected with 404 and the folder stays empty, while a member holding write access can still create chats there as intended.\n\nThe three accounts and the folder were created through the normal API. Nothing was written directly to the database.\n\n## Credits\nwhyiug, for reporting the missing folder write-access check on the chat-completions creation path.",
  "id": "GHSA-3pf7-q2g3-wj28",
  "modified": "2026-09-10T15:10:04Z",
  "published": "2026-09-10T15:10:04Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-3pf7-q2g3-wj28"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-87997"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/pull/28366"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/commit/d9e23b90c100d19b00270aea3cde0501d2354a6c"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-webui/open-webui"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/releases/tag/v0.11.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI: Any authenticated user can inject chats into another user\u0027s folder via chat completions"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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Action not permitted

CVE-2026-87997 (GCVE-0-2026-87997)

FKIE_CVE-2026-87997

GHSA-3PF7-Q2G3-WJ28

Summary

Preconditions

Impact

Fix

Root cause

Proof of concept

Credits

Tags

Sightings

Nomenclature

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