CVE Explorer

CVE-2026-4265

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to validate team-specific upload_file permissions which allows a guest user to post files in channels where they lack upload_file permission via uploading files in a team where they have permission and reusing the file metadata in a POST request to a different team. Mattermost Advisory ID: MMSA-2025-00553

Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:0a0b646cbbadea98b83a41a75a4b3983cd83aadc1db5ff60b4f4d374eb6643d7

Known exploited

Not asserted

Disputed

Stale source

Conflicts

Affected products and versions

1 source assertion

{"defaultStatus":"unaffected","product":"Mattermost","vendor":"Mattermost","versions":[{"lessThanOrEqual":"11.3.0","status":"affected","version":"11.3.0","versionType":"semver"},{"lessThanOrEqual":"11.2.2","status":"affected","version":"11.2.0","versionType":"semver"},{"lessThanOrEqual":"10.11.10","status":"affected","version":"10.11.0","versionType":"semver"},{"status":"unaffected","version":"11.4.0"},{"status":"unaffected","version":"11.3.1"},{"status":"unaffected","version":"11.2.3"},{"status":"unaffected","version":"10.11.11"}]}

cve_program_cvelist_v5affected
urn:baitaphish:normalized-source-record:v2:95cea4b4f67f2836193b72b4969f8f2b0b75d6ee2933ceca34c69f1ac84ba874 · sha256:decfb8a187893d75… · /containers/cna/affected/0

Provider-owned CVSS observations

1 source assertion

{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.3,"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:N","version":"3.1"},"metric_type":"cvssV3_1"}

cve_program_cvelist_v5cvss
urn:baitaphish:normalized-source-record:v2:95cea4b4f67f2836193b72b4969f8f2b0b75d6ee2933ceca34c69f1ac84ba874 · sha256:decfb8a187893d75… · /containers/cna/metrics/0/cvssV3_1

CWE assertions

1 source assertion

{"cweId":"CWE-863","description":"CWE-863: Incorrect Authorization","lang":"en","type":"CWE"}

cve_program_cvelist_v5cwe
urn:baitaphish:normalized-source-record:v2:95cea4b4f67f2836193b72b4969f8f2b0b75d6ee2933ceca34c69f1ac84ba874 · sha256:decfb8a187893d75… · /containers/cna/problemTypes/0/descriptions/0

Source references

1 source assertion

{"name":"MMSA-2025-00553","tags":["vendor-advisory"],"url":"https://mattermost.com/security-updates"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:95cea4b4f67f2836193b72b4969f8f2b0b75d6ee2933ceca34c69f1ac84ba874 · sha256:decfb8a187893d75… · /containers/cna/references/0

Attribution and limitations

CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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