CVE-2021-3967

Name: CVE-2021-3967
Creator: NVD / NIST
Published: 2022-02-26T23:15:08.83+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 0.85%

Last modified Jun 17, 2026

CVE-2021-3967 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. Improper Access Control in GitHub repository zulip/zulip prior to 4.10.. EPSS estimates a 0.85% chance of exploitation in the next 30 days.

Description

Improper Access Control in GitHub repository zulip/zulip prior to 4.10.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.85%

53.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-284

Affected Software

Vendor	Product	Versions
Zulip	Zulip	< 4.10

References

https://github.com/zulip/zulip/commit/d5db254ca8167995a1654d1c45ffc74b2fade39aPatch, Third Party Advisory
https://huntr.dev/bounties/2928a625-0467-4a0a-b4e2-e27322786686Exploit, Third Party Advisory
https://github.com/zulip/zulip/commit/d5db254ca8167995a1654d1c45ffc74b2fade39aPatch, Third Party Advisory
https://huntr.dev/bounties/2928a625-0467-4a0a-b4e2-e27322786686Exploit, Third Party Advisory

Timeline

Published: Feb 26, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3967?

Improper Access Control in GitHub repository zulip/zulip prior to 4.10.

How severe is CVE-2021-3967?

CVE-2021-3967 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.85% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3967?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3967?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST