CVE-2021-37860
Cross-site Scripting in Mattermost
Mattermost 5.38 and earlier fails to sufficiently sanitize clipboard contents, which allows a user-assisted attacker to inject arbitrary web script in product deployments that explicitly disable the default CSP.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Mattermost 5.38 and earlier fails to sufficiently sanitize clipboard contents, which allows a user-assisted attacker to inject arbitrary web script in product deployments that explicitly disable the default CSP.
- Record
CVE-2021-37860- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2021-2078
Mattermost 5.38 and earlier fails to sufficiently sanitize clipboard contents, which allows a user-assisted attacker to inject arbitrary web script in product deployments that explicitly disable the default CSP.
- Record
EUVD-2021-2078- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-hv5f-73mr-7vvj
Cross-site Scripting in Mattermost
Mattermost 5.38 and earlier fails to sufficiently sanitize clipboard contents, which allows a user-assisted attacker to inject arbitrary web script in product deployments that explicitly disable the default CSP.
- Record
GHSA-hv5f-73mr-7vvj- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
Mattermost 5.38 and earlier fails to sufficiently sanitize clipboard contents, which allows a user-assisted attacker to inject arbitrary web script in product deployments that explicitly disable the default CSP.
- Record
CVE-2021-37860- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 2.6 Low
AV:N/AC:H/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
Mattermost 5.38 and earlier fails to sufficiently sanitize clipboard contents, which allows a user-assisted attacker to inject arbitrary web script in product deployments that explicitly disable the default CSP.
- Record
CVE-2021-37860- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-hv5f-73mr-7vvj
Cross-site Scripting in Mattermost
Mattermost 5.38 and earlier fails to sufficiently sanitize clipboard contents, which allows a user-assisted attacker to inject arbitrary web script in product deployments that explicitly disable the default CSP.
- Record
GHSA-hv5f-73mr-7vvj- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVGO-2022-0604No score
Cross-site Scripting in Mattermost in github.com/mattermost/mattermost-server
Cross-site Scripting in Mattermost in github.com/mattermost/mattermost-server
- Record
GO-2022-0604- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/mattermost/mattermost-server/v5Go | before 5.39.0 | 5.39.0 |
github.com/mattermost/mattermost-serverGo | All versions | None known |
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-2021-37860 is a low vulnerability (CVSS 3.7) in Mattermost, published September 22, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.63%, the 50th percentile. Fixed in github.com/mattermost/mattermost-server/v5 5.39.0.