CVE-2021-3967
Improper Access Control in zulip/zulip
Improper Access Control in GitHub repository zulip/zulip prior to 4.10.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Improper Access Control in zulip/zulip
Improper Access Control in GitHub repository zulip/zulip prior to 4.10.
- Record
CVE-2021-3967- CVSS 3.0
- 4.1 Medium
CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:L - Weakness
- CWE-284
- Updated
- 2026-11-02
EUVDEUVD-2021-27172
Improper Access Control in GitHub repository zulip/zulip prior to 4.10.
- Record
EUVD-2021-27172- CVSS 3.0
- 4.1 Medium
CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:L - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-2xp9-33rm-wcwv
Improper Access Control in GitHub repository zulip/zulip prior to 4.10.
Improper Access Control in GitHub repository zulip/zulip prior to 4.10.
- Record
GHSA-2xp9-33rm-wcwv- 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 - Weakness
- CWE-287
- Updated
- 2026-11-02
NVD
Improper Access Control in GitHub repository zulip/zulip prior to 4.10.
- Record
CVE-2021-3967- 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 3.0
- 4.1 Medium
CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:L - CVSS 2.0
- 6.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:P - Weakness
- CWE-284
- Updated
- 2026-11-02
OSV
Improper Access Control in GitHub repository zulip/zulip prior to 4.10.
- Record
CVE-2021-3967- 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-2021-3967 is a medium vulnerability (CVSS 4.1) in Zulip, published February 26, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.84%, the 58th percentile. No source names a fixed version.