{"id":"CVE-2026-44558","aliases":["EUVD-2026-30621","GHSA-7rjh-px4v-5w55","PYSEC-2026-2711"],"status":"published","title":"Open WebUI: Channel Access Grants Bypass filter_allowed_access_grants","description":"Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the channel router does not call filter_allowed_access_grants on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework. This vulnerability is fixed in 0.9.0.","severity":{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.0019,"percentile":0.08791,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-862","CWE-863"],"published":"2026-05-08T19:50:51Z","modified":"2026-10-28T02:31:07Z","fixes":[{"ecosystem":"PyPI","package":"open-webui","fixed_in":["0.9.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"open-webui","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"0.8.12"},{"fixed":"0.9.0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"open-webui","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.0"}]}],"versions":["0.1.124","0.1.125","0.2.0","0.2.1","0.2.2","0.2.3","0.2.4","0.2.5","0.3.0","0.3.1","0.3.10","0.3.12","0.3.13","0.3.14","0.3.15","0.3.16","0.3.17","0.3.17.dev2","0.3.17.dev3","0.3.17.dev4","0.3.17.dev5","0.3.18","0.3.19","0.3.2","0.3.20","0.3.21","0.3.22","0.3.23","0.3.24","0.3.25","0.3.26","0.3.27","0.3.27.dev1","0.3.27.dev2","0.3.27.dev3","0.3.28","0.3.29","0.3.3","0.3.30","0.3.30.dev1","0.3.30.dev2","0.3.31","0.3.31.dev1","0.3.32","0.3.33","0.3.33.dev1","0.3.34","0.3.35","0.3.4","0.3.5","0.3.6","0.3.7","0.3.8","0.3.9","0.4.0","0.4.0.dev1","0.4.0.dev2","0.4.1","0.4.2","0.4.3","0.4.4","0.4.5","0.4.6","0.4.6.dev1","0.4.7","0.4.8","0.5.0","0.5.0.dev1","0.5.0.dev2","0.5.1","0.5.10","0.5.11","0.5.12","0.5.13","0.5.14","0.5.15","0.5.16","0.5.17","0.5.18","0.5.19","0.5.2","0.5.20","0.5.3","0.5.3.dev1","0.5.4","0.5.5","0.5.6","0.5.7","0.5.8","0.5.9","0.6.0","0.6.1","0.6.10","0.6.11","0.6.12","0.6.13","0.6.14","0.6.15","0.6.16","0.6.18","0.6.19","0.6.2","0.6.20","0.6.21","0.6.22","0.6.23","0.6.24","0.6.25","0.6.26","0.6.26.dev1","0.6.27","0.6.28","0.6.29","0.6.3","0.6.30","0.6.31","0.6.32","0.6.33","0.6.34","0.6.35","0.6.36","0.6.37","0.6.38","0.6.39","0.6.4","0.6.40","0.6.41","0.6.42","0.6.43","0.6.5","0.6.6","0.6.6.dev1","0.6.7","0.6.8","0.6.9","0.7.0","0.7.1","0.7.2","0.8.0","0.8.1","0.8.10","0.8.11","0.8.12","0.8.2","0.8.3","0.8.4","0.8.5","0.8.6","0.8.7","0.8.8","0.8.9"]},{"source":"osv","ecosystem":"PyPI","package":"open-webui","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.0"}]}],"versions":["0.1.124","0.1.125","0.2.0","0.2.1","0.2.2","0.2.3","0.2.4","0.2.5","0.3.0","0.3.1","0.3.10","0.3.12","0.3.13","0.3.14","0.3.15","0.3.16","0.3.17","0.3.17.dev2","0.3.17.dev3","0.3.17.dev4","0.3.17.dev5","0.3.18","0.3.19","0.3.2","0.3.20","0.3.21","0.3.22","0.3.23","0.3.24","0.3.25","0.3.26","0.3.27","0.3.27.dev1","0.3.27.dev2","0.3.27.dev3","0.3.28","0.3.29","0.3.3","0.3.30","0.3.30.dev1","0.3.30.dev2","0.3.31","0.3.31.dev1","0.3.32","0.3.33","0.3.33.dev1","0.3.34","0.3.35","0.3.4","0.3.5","0.3.6","0.3.7","0.3.8","0.3.9","0.4.0","0.4.0.dev1","0.4.0.dev2","0.4.1","0.4.2","0.4.3","0.4.4","0.4.5","0.4.6","0.4.6.dev1","0.4.7","0.4.8","0.5.0","0.5.0.dev1","0.5.0.dev2","0.5.1","0.5.10","0.5.11","0.5.12","0.5.13","0.5.14","0.5.15","0.5.16","0.5.17","0.5.18","0.5.19","0.5.2","0.5.20","0.5.3","0.5.3.dev1","0.5.4","0.5.5","0.5.6","0.5.7","0.5.8","0.5.9","0.6.0","0.6.1","0.6.10","0.6.11","0.6.12","0.6.13","0.6.14","0.6.15","0.6.16","0.6.18","0.6.19","0.6.2","0.6.20","0.6.21","0.6.22","0.6.23","0.6.24","0.6.25","0.6.26","0.6.26.dev1","0.6.27","0.6.28","0.6.29","0.6.3","0.6.30","0.6.31","0.6.32","0.6.33","0.6.34","0.6.35","0.6.36","0.6.37","0.6.38","0.6.39","0.6.4","0.6.40","0.6.41","0.6.42","0.6.43","0.6.5","0.6.6","0.6.6.dev1","0.6.7","0.6.8","0.6.9","0.7.0","0.7.1","0.7.2","0.8.0","0.8.1","0.8.10","0.8.11","0.8.12","0.8.2","0.8.3","0.8.4","0.8.5","0.8.6","0.8.7","0.8.8","0.8.9"]}],"products":[{"vendor":"open-webui","product":"open-webui"},{"vendor":"openwebui","product":"open_webui"}],"references":[{"url":"https://github.com/open-webui/open-webui/security/advisories/GHSA-7rjh-px4v-5w55","tags":["x_refsource_CONFIRM","exploit","Exploit","Vendor Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44558","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-7rjh-px4v-5w55","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44558.json","tags":["advisory"]},{"url":"https://github.com/open-webui/open-webui","tags":["package"]},{"url":"https://pypi.org/project/open-webui","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-44558","title":"Open WebUI: Channel Access Grants Bypass filter_allowed_access_grants","description":"Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the channel router does not call filter_allowed_access_grants on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework. This vulnerability is fixed in 0.9.0.","status":"published","published":"2026-05-15T19:43:40.12Z","modified":"2026-05-19T12:40:36.131Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T13:42:49.132798Z"}],"euvd":[{"id":"EUVD-2026-30621","description":"Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the channel router does not call filter_allowed_access_grants on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework. This vulnerability is fixed in 0.9.0.","status":"published","published":"2026-05-15T19:43:40Z","modified":"2026-05-19T12:40:36Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T18:21:15.688012Z"}],"ghsa":[{"id":"GHSA-7rjh-px4v-5w55","title":"Open WebUI's Channel Access Grants Bypass filter_allowed_access_grants","description":"# Channel Access Grants Bypass filter_allowed_access_grants\n\n## Affected Component\n\nChannel creation and update endpoints:\n- `backend/open_webui/routers/channels.py` (lines 291-340, `create_new_channel`)\n- `backend/open_webui/routers/channels.py` (lines 617-638, `update_channel_by_id`)\n- `backend/open_webui/models/channels.py` (lines 825-826, `set_access_grants` call without filtering)\n\n## Affected Versions\n\nCurrent main branch (commit `6fdd19bf1`) and likely all versions supporting user-created group channels with access grants.\n\n## Description\n\nAll resource routers in Open WebUI (knowledge, models, notes, prompts, tools, skills) call `filter_allowed_access_grants()` before persisting access grants. This function strips `principal_id: \"*\"` wildcard grants from users who lack the relevant `sharing.public_*` permission, and strips individual user grants from users who lack `access_grants.allow_users` permission.\n\nThe channel router does not call `filter_allowed_access_grants` on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework.\n\n```python\n# channels.py — access_grants from form data flow directly into persistence\n# No call to filter_allowed_access_grants() anywhere in these paths.\n\n# Compare with knowledge.py / models.py / notes.py / prompts.py / tools.py / skills.py,\n# all of which do:\n#     form_data.access_grants = filter_allowed_access_grants(user, form_data.access_grants)\n# before creating or updating.\n```\n\n## Attack Scenario\n\n1. Admin configures permissions so that regular users do NOT have `sharing.public_channels` — public sharing of channels is intended to be admin-only.\n2. Attacker (a regular user) creates or owns a group channel.\n3. Attacker sends:\n   ```\n   POST /api/v1/channels/\n   {\n     \"name\": \"public-channel\",\n     \"type\": \"group\",\n     \"access_control\": {\n       \"access_grants\": [\n         {\"principal_type\": \"user\", \"principal_id\": \"*\", \"permission\": \"read\"}\n       ]\n     }\n   }\n   ```\n4. `set_access_grants` is called directly without `filter_allowed_access_grants` — the wildcard grant is persisted.\n5. The channel becomes publicly readable to every user on the instance, despite the admin's policy prohibiting public channels for regular users.\n\nThe same attack works via `POST /api/v1/channels/{id}/update` for any channel the attacker owns.\n\n## Impact\n\n- Regular users can bypass the `sharing.public_channels` permission and make channels publicly accessible\n- Regular users can bypass `access_grants.allow_users` to grant individual-user access in environments where only group-based sharing is intended\n- Admin's permission framework for channels is silently ineffective\n- Creates an inconsistency with every other resource type in the codebase, making the security posture harder to reason about\n\n## Preconditions\n\n- Attacker must have an account with the ability to create group channels (default user capability), or ownership of an existing channel\n- Admin must have configured restrictive sharing permissions for regular users (otherwise there's no policy to bypass)","status":"published","published":"2026-05-08T19:50:51Z","modified":"2026-05-15T23:52:45Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-862","CWE-863"],"updated_at":"2026-11-02T14:40:11.298154Z"}],"nvd":[{"id":"CVE-2026-44558","description":"Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the channel router does not call filter_allowed_access_grants on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework. This vulnerability is fixed in 0.9.0.","status":"published","published":"2026-05-15T20:16:47.35Z","modified":"2026-06-17T10:50:47.433Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:12:19.39893Z"}],"osv":[{"id":"CVE-2026-44558","title":"Open WebUI: Channel Access Grants Bypass filter_allowed_access_grants","description":"Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the channel router does not call filter_allowed_access_grants on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework. This vulnerability is fixed in 0.9.0.","status":"published","published":"2026-05-15T19:43:40.12Z","modified":"2026-10-28T02:31:07.522455198Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T15:45:05.172514Z"},{"id":"GHSA-7rjh-px4v-5w55","title":"Open WebUI's Channel Access Grants Bypass filter_allowed_access_grants","description":"# Channel Access Grants Bypass filter_allowed_access_grants\n\n## Affected Component\n\nChannel creation and update endpoints:\n- `backend/open_webui/routers/channels.py` (lines 291-340, `create_new_channel`)\n- `backend/open_webui/routers/channels.py` (lines 617-638, `update_channel_by_id`)\n- `backend/open_webui/models/channels.py` (lines 825-826, `set_access_grants` call without filtering)\n\n## Affected Versions\n\nCurrent main branch (commit `6fdd19bf1`) and likely all versions supporting user-created group channels with access grants.\n\n## Description\n\nAll resource routers in Open WebUI (knowledge, models, notes, prompts, tools, skills) call `filter_allowed_access_grants()` before persisting access grants. This function strips `principal_id: \"*\"` wildcard grants from users who lack the relevant `sharing.public_*` permission, and strips individual user grants from users who lack `access_grants.allow_users` permission.\n\nThe channel router does not call `filter_allowed_access_grants` on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework.\n\n```python\n# channels.py — access_grants from form data flow directly into persistence\n# No call to filter_allowed_access_grants() anywhere in these paths.\n\n# Compare with knowledge.py / models.py / notes.py / prompts.py / tools.py / skills.py,\n# all of which do:\n#     form_data.access_grants = filter_allowed_access_grants(user, form_data.access_grants)\n# before creating or updating.\n```\n\n## Attack Scenario\n\n1. Admin configures permissions so that regular users do NOT have `sharing.public_channels` — public sharing of channels is intended to be admin-only.\n2. Attacker (a regular user) creates or owns a group channel.\n3. Attacker sends:\n   ```\n   POST /api/v1/channels/\n   {\n     \"name\": \"public-channel\",\n     \"type\": \"group\",\n     \"access_control\": {\n       \"access_grants\": [\n         {\"principal_type\": \"user\", \"principal_id\": \"*\", \"permission\": \"read\"}\n       ]\n     }\n   }\n   ```\n4. `set_access_grants` is called directly without `filter_allowed_access_grants` — the wildcard grant is persisted.\n5. The channel becomes publicly readable to every user on the instance, despite the admin's policy prohibiting public channels for regular users.\n\nThe same attack works via `POST /api/v1/channels/{id}/update` for any channel the attacker owns.\n\n## Impact\n\n- Regular users can bypass the `sharing.public_channels` permission and make channels publicly accessible\n- Regular users can bypass `access_grants.allow_users` to grant individual-user access in environments where only group-based sharing is intended\n- Admin's permission framework for channels is silently ineffective\n- Creates an inconsistency with every other resource type in the codebase, making the security posture harder to reason about\n\n## Preconditions\n\n- Attacker must have an account with the ability to create group channels (default user capability), or ownership of an existing channel\n- Admin must have configured restrictive sharing permissions for regular users (otherwise there's no policy to bypass)","status":"published","published":"2026-05-08T19:50:51Z","modified":"2026-07-13T16:43:21.071813592Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-862","CWE-863"],"updated_at":"2026-11-02T15:46:41.349637Z"},{"id":"PYSEC-2026-2711","title":"Open WebUI's Channel Access Grants Bypass filter_allowed_access_grants","description":"# Channel Access Grants Bypass filter_allowed_access_grants\n\n## Affected Component\n\nChannel creation and update endpoints:\n- `backend/open_webui/routers/channels.py` (lines 291-340, `create_new_channel`)\n- `backend/open_webui/routers/channels.py` (lines 617-638, `update_channel_by_id`)\n- `backend/open_webui/models/channels.py` (lines 825-826, `set_access_grants` call without filtering)\n\n## Affected Versions\n\nCurrent main branch (commit `6fdd19bf1`) and likely all versions supporting user-created group channels with access grants.\n\n## Description\n\nAll resource routers in Open WebUI (knowledge, models, notes, prompts, tools, skills) call `filter_allowed_access_grants()` before persisting access grants. This function strips `principal_id: \"*\"` wildcard grants from users who lack the relevant `sharing.public_*` permission, and strips individual user grants from users who lack `access_grants.allow_users` permission.\n\nThe channel router does not call `filter_allowed_access_grants` on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework.\n\n```python\n# channels.py — access_grants from form data flow directly into persistence\n# No call to filter_allowed_access_grants() anywhere in these paths.\n\n# Compare with knowledge.py / models.py / notes.py / prompts.py / tools.py / skills.py,\n# all of which do:\n#     form_data.access_grants = filter_allowed_access_grants(user, form_data.access_grants)\n# before creating or updating.\n```\n\n## Attack Scenario\n\n1. Admin configures permissions so that regular users do NOT have `sharing.public_channels` — public sharing of channels is intended to be admin-only.\n2. Attacker (a regular user) creates or owns a group channel.\n3. Attacker sends:\n   ```\n   POST /api/v1/channels/\n   {\n     \"name\": \"public-channel\",\n     \"type\": \"group\",\n     \"access_control\": {\n       \"access_grants\": [\n         {\"principal_type\": \"user\", \"principal_id\": \"*\", \"permission\": \"read\"}\n       ]\n     }\n   }\n   ```\n4. `set_access_grants` is called directly without `filter_allowed_access_grants` — the wildcard grant is persisted.\n5. The channel becomes publicly readable to every user on the instance, despite the admin's policy prohibiting public channels for regular users.\n\nThe same attack works via `POST /api/v1/channels/{id}/update` for any channel the attacker owns.\n\n## Impact\n\n- Regular users can bypass the `sharing.public_channels` permission and make channels publicly accessible\n- Regular users can bypass `access_grants.allow_users` to grant individual-user access in environments where only group-based sharing is intended\n- Admin's permission framework for channels is silently ineffective\n- Creates an inconsistency with every other resource type in the codebase, making the security posture harder to reason about\n\n## Preconditions\n\n- Attacker must have an account with the ability to create group channels (default user capability), or ownership of an existing channel\n- Admin must have configured restrictive sharing permissions for regular users (otherwise there's no policy to bypass)","status":"published","published":"2026-07-13T15:15:42.033605Z","modified":"2026-07-13T16:32:18.740039547Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:52:55.961245Z"}]}}