{"id":"CVE-2026-53837","aliases":["EUVD-2026-36625","GHSA-chqm-wxm2-w73w","GHSA-gp79-m99v-gjmh"],"status":"published","title":"OpenClaw \u003c 2026.5.6 - Missing Channel Type Validation in Mattermost Event Handlers","description":"OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted content.","severity":{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00189,"percentile":0.08585,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-636"],"published":"2026-06-12T21:57:00Z","modified":"2026-10-28T02:30:36Z","fixes":[{"ecosystem":"npm","package":"openclaw","fixed_in":["2026.5.6"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"openclaw","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2026.5.5"},{"fixed":"2026.5.6"}]}]},{"source":"osv","ecosystem":"npm","package":"openclaw","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2026.5.6"}]}]}],"products":[{"vendor":"openclaw","product":"openclaw"}],"references":[{"url":"https://github.com/openclaw/openclaw/security/advisories/GHSA-gp79-m99v-gjmh","tags":["vendor-advisory","Mitigation","Vendor Advisory","advisory","web"]},{"url":"https://www.vulncheck.com/advisories/openclaw-missing-channel-type-validation-in-mattermost-event-handlers","tags":["third-party-advisory","Third Party Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53837","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-chqm-wxm2-w73w"},{"url":"https://github.com/advisories/GHSA-gp79-m99v-gjmh"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53837.json","tags":["advisory"]},{"url":"https://github.com/openclaw/openclaw","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-53837","title":"OpenClaw \u003c 2026.5.6 - Missing Channel Type Validation in Mattermost Event Handlers","description":"OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted content.","status":"published","published":"2026-06-12T21:57:00.613Z","modified":"2026-06-15T15:10:01.881Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna"},{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-636"],"updated_at":"2026-11-02T14:20:00.11477Z"}],"euvd":[{"id":"EUVD-2026-36625","description":"OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted content.","status":"published","published":"2026-06-12T21:57:00Z","modified":"2026-06-15T15:10:01Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T18:20:41.888684Z"}],"ghsa":[{"id":"GHSA-chqm-wxm2-w73w","title":"Duplicate Advisory: OpenClaw: Mattermost handlers could fall open when channel type was missing","description":"### Duplicate Advisory\nThis advisory has been withdrawn because it is a duplicate of GHSA-gp79-m99v-gjmh. This link is maintained to preserve external references.\n\n### Original Description\nOpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted content.","status":"withdrawn","published":"2026-06-13T00:34:33Z","modified":"2026-08-28T15:53:22Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"},{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"low"}],"cwes":["CWE-636"],"updated_at":"2026-11-02T14:41:07.031507Z"},{"id":"GHSA-gp79-m99v-gjmh","title":"OpenClaw: Mattermost handlers could fall open when channel type was missing","description":"### Summary\n\nMattermost handlers could fall open when channel type was missing. In affected versions, a Mattermost event missing channel type metadata could continue without applying the intended DM policy decision.\n\nThis advisory is scoped to the named feature and configuration. It does not change OpenClaw's trusted-operator model: authenticated Gateway operators, installed plugins, and intentional local execution surfaces remain trusted unless a separate policy, approval, allowlist, sandbox, or auth boundary is crossed.\n\n### Impact\n\nWhen the affected feature is enabled and reachable, this could process a Mattermost event that should have been gated by channel policy. Practical impact depends on the operator's configuration and whether lower-trust input can reach that path.\n\n### Patched Versions\n\nThe first stable patched version is `2026.5.6`.\n\n### Mitigations\n\nkeep Mattermost bot access restricted and review channel metadata errors until patched. As general hardening, keep channel and tool allowlists narrow, avoid sharing one Gateway between mutually untrusted users, and disable the affected feature when it is not needed.","status":"published","published":"2026-07-02T16:45:14Z","modified":"2026-08-28T15:53:32Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"},{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"low"}],"cwes":["CWE-636"],"updated_at":"2026-11-02T14:41:07.031507Z"}],"nvd":[{"id":"CVE-2026-53837","description":"OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted content.","status":"published","published":"2026-06-12T22:16:55.567Z","modified":"2026-07-23T09:10:00.113Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"low","assessor":"secondary"},{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-636"],"updated_at":"2026-11-02T14:12:23.846948Z"}],"osv":[{"id":"CVE-2026-53837","title":"OpenClaw \u003c 2026.5.6 - Missing Channel Type Validation in Mattermost Event Handlers","description":"OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted content.","status":"published","published":"2026-06-12T21:57:00.613Z","modified":"2026-10-28T02:30:36.769010316Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-636"],"updated_at":"2026-11-02T15:45:08.132336Z"},{"id":"GHSA-chqm-wxm2-w73w","title":"Duplicate Advisory: OpenClaw: Mattermost handlers could fall open when channel type was missing","description":"### Duplicate Advisory\nThis advisory has been withdrawn because it is a duplicate of GHSA-gp79-m99v-gjmh. This link is maintained to preserve external references.\n\n### Original Description\nOpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted content.","status":"withdrawn","published":"2026-06-13T00:34:33Z","modified":"2026-08-28T16:00:07.764447268Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"low"},{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-636"],"updated_at":"2026-11-02T15:46:45.28161Z"},{"id":"GHSA-gp79-m99v-gjmh","title":"OpenClaw: Mattermost handlers could fall open when channel type was missing","description":"### Summary\n\nMattermost handlers could fall open when channel type was missing. In affected versions, a Mattermost event missing channel type metadata could continue without applying the intended DM policy decision.\n\nThis advisory is scoped to the named feature and configuration. It does not change OpenClaw's trusted-operator model: authenticated Gateway operators, installed plugins, and intentional local execution surfaces remain trusted unless a separate policy, approval, allowlist, sandbox, or auth boundary is crossed.\n\n### Impact\n\nWhen the affected feature is enabled and reachable, this could process a Mattermost event that should have been gated by channel policy. Practical impact depends on the operator's configuration and whether lower-trust input can reach that path.\n\n### Patched Versions\n\nThe first stable patched version is `2026.5.6`.\n\n### Mitigations\n\nkeep Mattermost bot access restricted and review channel metadata errors until patched. As general hardening, keep channel and tool allowlists narrow, avoid sharing one Gateway between mutually untrusted users, and disable the affected feature when it is not needed.","status":"published","published":"2026-07-02T16:45:14Z","modified":"2026-08-28T16:00:07.755038258Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","level":"low"},{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-636"],"updated_at":"2026-11-02T15:46:48.191583Z"}]}}