Vulnerability-Lookup

CVE-2026-70481 (GCVE-0-2026-70481)

Vulnerability from cvelistv5 – Published: 2026-08-04 19:45 – Updated: 2026-08-04 19:45

Title

Open WebUI: Any member with write access to a standard channel can edit or delete other members' messages

Summary

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.5.0 until 0.11.0, the standard channel message update and delete handlers accepted any caller holding write access on the channel without checking that the caller wrote the message. Because write access is the same grant a member needs to post, any ordinary participant in a shared standard channel could rewrite or permanently delete another participant message, while group and direct message handlers enforced authorship. This issue is fixed in 0.11.0.

Severity

5.4 (Medium)


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

CWE

CWE-284 - Improper Access Control
CWE-862 - Missing Authorization

Assigner

GitHub_M

References

4 references

URL	Tags
https://github.com/open-webui/open-webui/security…	x_refsource_CONFIRM
https://github.com/open-webui/open-webui/pull/27197	x_refsource_MISC
https://github.com/open-webui/open-webui/commit/c…	x_refsource_MISC
https://github.com/open-webui/open-webui/releases…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
open-webui	open-webui	Affected: >= 0.5.0, < 0.11.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "open-webui",
          "vendor": "open-webui",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.5.0, \u003c 0.11.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.5.0 until 0.11.0, the standard channel message update and delete handlers accepted any caller holding write access on the channel without checking that the caller wrote the message. Because write access is the same grant a member needs to post, any ordinary participant in a shared standard channel could rewrite or permanently delete another participant message, while group and direct message handlers enforced authorship. This issue is fixed in 0.11.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-284",
              "description": "CWE-284: Improper Access Control",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-862",
              "description": "CWE-862: Missing Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-04T19:45:37.332Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/open-webui/open-webui/security/advisories/GHSA-mj5r-jf49-m3w7",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-mj5r-jf49-m3w7"
        },
        {
          "name": "https://github.com/open-webui/open-webui/pull/27197",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/open-webui/open-webui/pull/27197"
        },
        {
          "name": "https://github.com/open-webui/open-webui/commit/c609ec41154fa092fa0af80d9d365de06b666286",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/open-webui/open-webui/commit/c609ec41154fa092fa0af80d9d365de06b666286"
        },
        {
          "name": "https://github.com/open-webui/open-webui/releases/tag/v0.11.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/open-webui/open-webui/releases/tag/v0.11.0"
        }
      ],
      "source": {
        "advisory": "GHSA-mj5r-jf49-m3w7",
        "discovery": "UNKNOWN"
      },
      "title": "Open WebUI: Any member with write access to a standard channel can edit or delete other members\u0027 messages"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-70481",
    "datePublished": "2026-08-04T19:45:37.332Z",
    "dateReserved": "2026-08-04T15:24:41.339Z",
    "dateUpdated": "2026-08-04T19:45:37.332Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-70481\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-08-04T20:16:55.050\",\"lastModified\":\"2026-08-04T20:16:55.050\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.5.0 until 0.11.0, the standard channel message update and delete handlers accepted any caller holding write access on the channel without checking that the caller wrote the message. Because write access is the same grant a member needs to post, any ordinary participant in a shared standard channel could rewrite or permanently delete another participant message, while group and direct message handlers enforced authorship. This issue is fixed in 0.11.0.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"open-webui\",\"product\":\"open-webui\",\"versions\":[{\"version\":\"\u003e= 0.5.0, \u003c 0.11.0\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L\",\"baseScore\":5.4,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"LOW\"},\"exploitabilityScore\":2.8,\"impactScore\":2.5}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-284\"},{\"lang\":\"en\",\"value\":\"CWE-862\"}]}],\"references\":[{\"url\":\"https://github.com/open-webui/open-webui/commit/c609ec41154fa092fa0af80d9d365de06b666286\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/open-webui/open-webui/pull/27197\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/open-webui/open-webui/releases/tag/v0.11.0\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/open-webui/open-webui/security/advisories/GHSA-mj5r-jf49-m3w7\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}

GHSA-MJ5R-JF49-M3W7

Vulnerability from github – Published: 2026-08-04 19:45 – Updated: 2026-08-04 19:45

Summary

Open WebUI: Any member with write access to a standard channel can edit or delete other members' messages

Details

Summary

On standard channels, the message update and delete handlers accepted any caller holding write access on the channel, without checking that the caller wrote the message. Write access is the same grant a member needs in order to post, so every ordinary participant in a shared channel could rewrite or permanently delete any other participant's messages. The group and direct message branch of the same handlers enforced authorship; the standard branch did not.

Preconditions

Channels are disabled by default and must be enabled by an administrator (ENABLE_CHANNELS). The channel must be a standard channel; group and direct message channels are not affected. The attacker is any authenticated account with role user that holds write access on the channel, whether granted publicly, per user, or through a group. No ownership of the channel, channel manager role, or elevated role is required. Channel and message ids are returned by the listing endpoints the member can already call.

Impact

An ordinary member could replace the content of another member's message while the message stayed attributed to its original author, and could attach arbitrary data and meta payloads to it through the same form. The member could also permanently delete other members' messages, up to the entire visible history of the channel. This is an integrity and availability loss against other users of the channel: content can be forged under a colleague's name and records can be destroyed. It reaches no further than channels the attacker already has write access to, and it discloses nothing the attacker could not already read as a member. Pinning is unaffected and is not part of this issue.

Fix

Fixed in c609ec411 (#27197), released in 0.11.0. Both handlers now apply the same authorship check the group and direct message branch already used, so a non-admin caller can act only on their own messages regardless of write access. Upgrading fully resolves it, with no configuration change required.

Root cause

Affected components: - backend/open_webui/routers/channels.py, update_message_by_id (POST /api/v1/channels/{id}/messages/{message_id}/update) - backend/open_webui/routers/channels.py, delete_message_by_id (DELETE /api/v1/channels/{id}/messages/{message_id}/delete)

Both handlers branch on channel type, and the two branches asked different questions. The group and direct message branch asked whether the caller wrote the message. The standard branch asked whether the caller is allowed to write in the channel, which is a permission level, not an identity. Those are not interchangeable: posting a message runs that same write check, so the grant that lets a member participate was silently accepted as the grant to rewrite and remove everyone else's content, and every ordinary participant satisfied it. The model layer looks messages up by primary key alone, so the router branch was the only authorization that ran.

Proof of concept

Reported with a script that runs end to end against a live instance. An administrator seeds the accounts and a standard channel granting read and write; everything after that is performed by a separate plain user account in no group that owns neither the channel nor any of the messages. That account edits a victim's message, attaches structured payloads to it, and deletes a second victim message, all returning 200, with the channel history dumped before and after. Controls in the same run confirm the scoping: a read-only member is refused with 403, and a cross-member edit on a group channel is refused with 403.

Credits

@Foxer131 — reported the missing authorship check on the standard-channel update and delete handlers.

Severity

5.4 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.10.2"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.5.0"
            },
            {
              "fixed": "0.11.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-70481"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284",
      "CWE-862"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-04T19:45:39Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\nOn standard channels, the message update and delete handlers accepted any caller holding write access on the channel, without checking that the caller wrote the message. Write access is the same grant a member needs in order to post, so every ordinary participant in a shared channel could rewrite or permanently delete any other participant\u0027s messages. The group and direct message branch of the same handlers enforced authorship; the standard branch did not.\n\n## Preconditions\nChannels are disabled by default and must be enabled by an administrator (`ENABLE_CHANNELS`). The channel must be a standard channel; group and direct message channels are not affected. The attacker is any authenticated account with role `user` that holds write access on the channel, whether granted publicly, per user, or through a group. No ownership of the channel, channel manager role, or elevated role is required. Channel and message ids are returned by the listing endpoints the member can already call.\n\n## Impact\nAn ordinary member could replace the content of another member\u0027s message while the message stayed attributed to its original author, and could attach arbitrary `data` and `meta` payloads to it through the same form. The member could also permanently delete other members\u0027 messages, up to the entire visible history of the channel. This is an integrity and availability loss against other users of the channel: content can be forged under a colleague\u0027s name and records can be destroyed. It reaches no further than channels the attacker already has write access to, and it discloses nothing the attacker could not already read as a member. Pinning is unaffected and is not part of this issue.\n\n## Fix\nFixed in `c609ec411` (#27197), released in 0.11.0. Both handlers now apply the same authorship check the group and direct message branch already used, so a non-admin caller can act only on their own messages regardless of write access. Upgrading fully resolves it, with no configuration change required.\n\n## Root cause\nAffected components:\n- `backend/open_webui/routers/channels.py`, `update_message_by_id` (`POST /api/v1/channels/{id}/messages/{message_id}/update`)\n- `backend/open_webui/routers/channels.py`, `delete_message_by_id` (`DELETE /api/v1/channels/{id}/messages/{message_id}/delete`)\n\nBoth handlers branch on channel type, and the two branches asked different questions. The group and direct message branch asked whether the caller wrote the message. The standard branch asked whether the caller is allowed to write in the channel, which is a permission level, not an identity. Those are not interchangeable: posting a message runs that same write check, so the grant that lets a member participate was silently accepted as the grant to rewrite and remove everyone else\u0027s content, and every ordinary participant satisfied it. The model layer looks messages up by primary key alone, so the router branch was the only authorization that ran.\n\n## Proof of concept\nReported with a script that runs end to end against a live instance. An administrator seeds the accounts and a standard channel granting read and write; everything after that is performed by a separate plain `user` account in no group that owns neither the channel nor any of the messages. That account edits a victim\u0027s message, attaches structured payloads to it, and deletes a second victim message, all returning 200, with the channel history dumped before and after. Controls in the same run confirm the scoping: a read-only member is refused with 403, and a cross-member edit on a group channel is refused with 403.\n\n## Credits\n@Foxer131 \u2014 reported the missing authorship check on the standard-channel update and delete handlers.",
  "id": "GHSA-mj5r-jf49-m3w7",
  "modified": "2026-08-04T19:45:39Z",
  "published": "2026-08-04T19:45:39Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-mj5r-jf49-m3w7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/pull/27197"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/commit/c609ec41154fa092fa0af80d9d365de06b666286"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-webui/open-webui"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/releases/tag/v0.11.0"
    }
  ],
  "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:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI: Any member with write access to a standard channel can edit or delete other members\u0027 messages"
}

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.

Action not permitted

CVE-2026-70481 (GCVE-0-2026-70481)

GHSA-MJ5R-JF49-M3W7

Summary

Preconditions

Impact

Fix

Root cause

Proof of concept

Credits

Tags

Sightings

Nomenclature