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TI-2021-10879 Aliases CVE-2021-30477GHSA-45v2-23j7-x684

An issue was discovered in Zulip Server before 3.4.

Priority LOW 21Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · Low · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA.

Summary

An issue was discovered in Zulip Server before 3.4. A bug in the implementation of replies to messages sent by outgoing webhooks to private streams meant that an outgoing webhook bot could be used to send messages to private streams that the user was not intended to be able to send messages to.

Why it matters now

EPSS 0.00656 51st percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:zulip:zulip_server:*:*:*:*:*:*:*:*before 3.4Vulnerablezulip
  • cpe:2.3:a:zulip:zulip_server:*:*:*:*:*:*:*:* Versions before 3.4 Vulnerable ·zulip

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-30477
  2. 2026-10-03 Alias added: GHSA-45v2-23j7-x684
  3. 2026-10-13 EPSS moved to the 50th–90th percentile

References

Advisory 1

  • TI-2024-37129 /api/v1/jwt/fetch_api_key endpoint can leak if an email address has an account in Zulip server CVSS 4.0MEDIUM 6.9
  • TI-2022-06082 Multi-use invitations can grant access to other organizations in Zulip CVSS 3.1CRITICAL 9.8
  • TI-2019-13649 In Zulip Server versions from 1.7.0 to before 2.0.7, a bug in the new user signup process… CVSS 3.1CRITICAL 9.8
  • TI-2025-22659 Zulip Authentication Backend Configuration Bypass CVSS 3.1HIGH 8.2
  • TI-2024-24345 Zulip from 8.0 to 8.3 contains a memory leak vulnerability in the handling of popovers. CVSS 3.1HIGH 7.5
  • TI-2020-11848 Zulip Server 2.x before 2.1.7 allows eval injection if a privileged attacker were able to… CVSS 3.1HIGH 8.8
See all 39 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences