Zulip vulnerabilities: known CVEs & security history
Zulip · Collaboration · 20 tracked CVEs · 0 actively exploited · updated June 2026 · what is a CVE? →
This is the full list of known vulnerabilities (CVEs) across all Zulip release lines — 20 in total. A CVE here doesn't mean your version is affected — check Zulip's current status and the safe version to run.
Known Zulip CVEs
Actively-exploited and most-severe first. Open any CVE for full details.
| CVE | Severity | CVSS | EPSS | Year |
|---|---|---|---|---|
| CVE-2021-3967 | high | 8.8 | 1% | 2022 |
| CVE-2021-43799 | high | 8.6 | 5% | 2022 |
| CVE-2022-35962 | high | 8 | 1% | 2022 |
| CVE-2016-4427 | high | 7.5 | 1% | 2022 |
| CVE-2023-28623 | medium | 6.5 | 1% | 2023 |
| CVE-2021-43791 | medium | 6.5 | 1% | 2021 |
| CVE-2026-26058 | medium | 6.1 | 0% | 2026 |
| CVE-2024-36624 | medium | 5.4 | 0% | 2024 |
| CVE-2024-36625 | medium | 5.4 | 0% | 2024 |
| CVE-2022-31168 | medium | 5.4 | 1% | 2022 |
| CVE-2022-24751 | medium | 5.4 | 1% | 2022 |
| CVE-2021-3866 | medium | 5.4 | 1% | 2022 |
| CVE-2026-25742 | medium | 5.3 | 0% | 2026 |
| CVE-2025-47930 | medium | 5.3 | 0% | 2025 |
| CVE-2022-36048 | medium | 4.3 | 0% | 2022 |
| CVE-2016-4426 | medium | 4.3 | 0% | 2022 |
| CVE-2021-41115 | medium | 4.3 | 2% | 2021 |
| CVE-2023-32677 | low | 3.1 | 1% | 2023 |
| CVE-2025-30368 | low | 2.7 | 0% | 2025 |
| CVE-2022-31017 | low | 2 | 0% | 2022 |
Is my Zulip version affected?
The list above spans every release. To know whether your version is affected — and the minimum safe version to upgrade to — check it directly.
Check your Zulip version → · Monitor Zulip for new CVEs →
Zulip vulnerabilities — frequently asked
How many known vulnerabilities does Zulip have?
IsItPatched tracks 20 CVEs for Zulip. 0 are critical-severity and 4 high-severity. These span every release line — what matters is whether the version you run is affected.
Does Zulip have any actively-exploited vulnerabilities?
None of Zulip's tracked CVEs are currently in CISA's KEV catalog — but new ones can be added at any time, so keep your version current.
What is the most severe Zulip vulnerability?
Among tracked issues, CVE-2021-3967 (HIGH, CVSS 8.8) ranks highest — a Improper access control weakness.
Is Zulip safe to use?
It depends on the version. The latest supported Zulip release clears the known issues; older versions may still be affected. Check the exact version you run for a verdict.
CVE data aggregated from NVD, CISA KEV and EPSS (FIRST.org). Related: Zulip security status · Zulip end-of-life · actively-exploited CVEs. Always verify against Zulip's advisories — see our disclaimer.