Cyber Resilience

CVE-2021-30479

Medium

Published: 15 April 2021

Published
15 April 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS Score 0.0020 42.3th percentile
Risk Priority 11 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-30479 is a medium-severity Improper Privilege Management (CWE-269) vulnerability in Zulip Zulip Server. Its CVSS base score is 5.3 (Medium).

Operationally, ranked at the 42.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

An issue was discovered in Zulip Server before 3.4. A bug in the implementation of the all_public_streams API feature resulted in guest users being able to receive message traffic to public streams that should have been only accessible to members…

more

of the organization.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

zulip
zulip server
≤ 3.4

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-269

Policy addresses roles, responsibilities, and privilege management to prevent improper privilege assignments.

addresses: CWE-269

Access supervision ensures privileges are assigned and managed without improper escalation or retention.

addresses: CWE-269

Assigning group/role memberships and access authorizations (privileges) while reviewing accounts addresses improper privilege management.

addresses: CWE-269

Enforces proper privilege management by requiring all decisions through the verified reference monitor.

addresses: CWE-269

By mandating division of duties across roles, the control enforces proper privilege management and prevents a single entity from controlling an entire sensitive process.

addresses: CWE-269

Implements core proper privilege management by restricting to only required rights.

addresses: CWE-269

Policy requires training on privilege management and least privilege, making it harder to exploit improper privilege management weaknesses.

addresses: CWE-269

Training covers proper privilege management practices, making incorrect privilege assignments less likely.

References