CVE Explorer
CVE-2026-5163
Mattermost versions 11.5.x <= 11.5.1 fail to verify channel membership when processing AI-assisted message rewrites which allows an authenticated attacker to read the content of threads in private channels and direct messages they do not have access to via a crafted request to the post rewrite endpoint.. Mattermost Advisory ID: MMSA-2026-00645
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"defaultStatus":"unaffected","product":"Mattermost","vendor":"Mattermost","versions":[{"lessThanOrEqual":"11.5.1","status":"affected","version":"11.5.0","versionType":"semver"},{"status":"unaffected","version":"11.6.0"},{"status":"unaffected","version":"11.5.2"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:487db76543dd9207c6ab63cf3afdea7b726de2e5430bab6beb6aec9bcbf86c5f · sha256:ea82ac8dbee182c5… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:487db76543dd9207c6ab63cf3afdea7b726de2e5430bab6beb6aec9bcbf86c5f · sha256:ea82ac8dbee182c5… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-862","description":"CWE-862: Missing Authorization","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:487db76543dd9207c6ab63cf3afdea7b726de2e5430bab6beb6aec9bcbf86c5f · sha256:ea82ac8dbee182c5… · /containers/cna/problemTypes/0/descriptions/0
Source references
1 source assertion{"name":"MMSA-2026-00645","tags":["vendor-advisory"],"url":"https://mattermost.com/security-updates"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:487db76543dd9207c6ab63cf3afdea7b726de2e5430bab6beb6aec9bcbf86c5f · sha256:ea82ac8dbee182c5… · /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.