01 Record
CVE-2021-30477
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
UnratedPUBLISHEDCNA: mitre
CNA base scoreUnratedNo CNA CVSS vector
02 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
03 Exploitation and scoring
- Exploitation
- Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
- SSVC decision
- Not assessed by CISA
- EPSS probability
- 0.65% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 50.8% of scored records. A rank, not a probability.
- NVD base score
- 4.3 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- NVD analysis status
- Modified. NVD last modified this record on 2026-06-17.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2021-04-14 23:45Z5 YR AGO
- Last updated
- 2024-08-03 22:32Z2 YR AGO
- Reserved
- 2021-04-09
- Assigning CNA
- mitre
- Record state
- PUBLISHED
- Severity
- Not rated by the issuing CNA
- CNA CVSS vector
- Not published by the issuing CNA
- Weaknesses
- No CWE assigned
- Data version
- 5.1
- Document digest
- 1fb30694e550ce044463e2d63bea880e66acda83919640b5ee5790ee2283173d
05 Affected products
VendorProductVersionsPlatforms
06 References
- blog.zulip.comhttps://blog.zulip.com/2021/04/14/zulip-server-3-4/