CVE-2021-30477
An issue was discovered in Zulip Server before 3.4.
Does this matter?
Lower severity and a low EPSS score (0.66%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 3.1
- 4.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- EPSS
- 0.66% probability · 51th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Affected
- zulip/zulip server
- Source
- cve@mitre.org
EPSS 0.7% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://blog.zulip.com/2021/04/14/zulip-server-3-4/Release Notes, Vendor Advisory
- https://blog.zulip.com/2021/04/14/zulip-server-3-4/Release Notes, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.