Medium severity · published Apr 14, 2021
CVE-2021-30477
An issue was discovered in Zulip Server before 3.4
4.3
CVSS
0.7%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 51% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZS
Zulip Server · Zulip
before 3.4 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-30477
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-30477
Release Notes
https://blog.zulip.com/2021/04/14/zulip-server-3-4/
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