Account Takeover via Substring Matching in OpenID Connect Authentication
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Mattermost | Mattermost | unaffected |
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Configuration 1 [-]
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No data.
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| Mattermost | Mattermost |
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Vendor Solution
Update Mattermost to versions 11.5.0, 11.4.1, 11.3.2, 11.2.4, 10.11.12 or higher.
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-fg35-5rf6-qg3g | Mattermost allows attackers to take over arbitrary user accounts via overly permissive substring matching flaw |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.187% probability within 30 days)
| Link | Providers |
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| https://mattermost.com/security-updates |
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| First Time appeared |
Mattermost mattermost Server
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| CPEs | cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Mattermost mattermost Server
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| Metrics |
ssvc
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| First Time appeared |
Mattermost
Mattermost mattermost |
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| Vendors & Products |
Mattermost
Mattermost mattermost |
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| Description | Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to properly validate user identity in the OpenID {{IsSameUser()}} comparison logic, which allows an attacker to take over arbitrary user accounts via an overly permissive substring matching flaw in the user discovery flow.. Mattermost Advisory ID: MMSA-2026-00590 | |
| Title | Account Takeover via Substring Matching in OpenID Connect Authentication | |
| Weaknesses | CWE-303 | |
| References |
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| Metrics |
cvssV3_1
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