How severe is CVE-2021-30487?

CVE-2021-30487 has a CVSS 3.x base score of 2.7, rated low severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2021-30487 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-30487?

CVE-2021-30487 affects Zulip Zulip Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-30487?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-30487 published?

CVE-2021-30487 was published on 2021-04-15 and last updated on 2026-06-17.

CVE-2021-30487

CVE-2021-30487 is a low-severity vulnerability in Zulip Zulip Server with a CVSS 3.x base score of 2.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Low (CVSS 3.x base score 2.7)
CVSS v2: 4.0
EPSS exploit prediction: 1% (47th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Zulip Zulip Server
Published: 2021-04-15
Last modified: 2026-06-17

Description

In the topic moving API in Zulip Server 3.x before 3.4, organization administrators were able to move messages to streams in other organizations hosted by the same Zulip installation.

Frequently asked questions

What is CVE-2021-30487?: In the topic moving API in Zulip Server 3.x before 3.4, organization administrators were able to move messages to streams in other organizations hosted by the same Zulip installation.
How severe is CVE-2021-30487?: CVE-2021-30487 has a CVSS 3.x base score of 2.7, rated low severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2021-30487 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-30487?: CVE-2021-30487 affects Zulip Zulip Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-30487?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-30487 published?: CVE-2021-30487 was published on 2021-04-15 and last updated on 2026-06-17.

References

https://blog.zulip.com/2021/04/14/zulip-server-3-4/

Affected products (1)

cpe:2.3:a:zulip:zulip_server:*:*:*:*:*:*:*:*

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