CVE-2018-21263
An issue was discovered in Mattermost Server before 4.7.0, 4.6.2, and 4.5.2. An attacker could...
An issue was discovered in Mattermost Server before 4.7.0, 4.6.2, and 4.5.2. An attacker could authenticate to a different user's account via a crafted SAML response.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in Mattermost Server before 4.7.0, 4.6.2, and 4.5.2. An attacker could authenticate to a different user's account via a crafted SAML response.
- Record
CVE-2018-21263- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:P - Weakness
- CWE-287
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in Mattermost Server before 4.7.0, 4.6.2, and 4.5.2. An attacker could authenticate to a different user's account via a crafted SAML response.
- Record
CVE-2018-21263- Updated
- 2026-11-02
EUVDEUVD-2018-13778 No score
An issue was discovered in Mattermost Server before 4.7.0, 4.6.2, and 4.5.2. An attacker could authenticate to a different user's account via a crafted SAML response.
- Record
EUVD-2018-13778- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-c3c7-jrp2-v7vx No score
An issue was discovered in Mattermost Server before 4.7.0, 4.6.2, and 4.5.2. An attacker could...
An issue was discovered in Mattermost Server before 4.7.0, 4.6.2, and 4.5.2. An attacker could authenticate to a different user's account via a crafted SAML response.
- Record
GHSA-c3c7-jrp2-v7vx- Updated
- 2026-11-02
OSV
An issue was discovered in Mattermost Server before 4.7.0, 4.6.2, and 4.5.2. An attacker could authenticate to a different user's account via a crafted SAML response.
- Record
CVE-2018-21263- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2018-21263 is a high vulnerability (CVSS 8.8) in Mattermost Server, published June 19, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.93%, the 60th percentile. No source names a fixed version.