Vulnerability in Zulip
CVE-2021-43791
Zulip is an open source group chat application that combines real-time chat with threaded conversations. In affected versions expiration dates on the confirmation objects associated with email invitations were not enforced properly in the new account registration flow. A confirmation link takes a user to the check_prereg_key_and_redirect endpoint, before getting redirected to POST to /accounts/register/. The problem was that validation was happening in the check_prereg_key_and_redirect part and not in /accounts/register/ - meaning that one could submit an expired confirmation key and be able to register. The issue is fixed in Zulip 4.8. There are no known workarounds and users are advised to upgrade as soon as possible.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.007 (51.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.007 · change: +0.000
Affected products
- Zulip — versions < 4.8
Weakness classification (CWE)
References
- github.com/zulip/zulip/security/advisories/GHSA-wj76-pcqr-mf9f (Third Party Advisory)
- github.com/zulip/zulip/commit/a014ef75a3a0ed7f24ebb157632ba58751e732c6 (Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-43791?
- CVE-2021-43791 is a medium-severity vulnerability in Zulip, classified under Insufficient Session Expiration. CVSS score: 6.5/10. Published 2021-12-02.
- How severe is CVE-2021-43791?
- Medium severity. CVSS v3 base score is 6.5 out of 10.