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Fencer Intel
medium 4.3

CVE-2021-30478 json

An issue was discovered in Zulip Server before 3.4.

published 5y ago modified 4mo ago also EUVD-2021-17401

cvss
4.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

An issue was discovered in Zulip Server before 3.4. A bug in the implementation of the can_forge_sender permission (previously is_api_super_user) resulted in users with this permission being able to send messages appearing as if sent by a system bot, including to other organizations hosted by the same Zulip installation.

Patch / fix

  • zulip zulip_server 3.4

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Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:P/A:N

Classification

Weakness
  • CWE-269 Improper Privilege Management

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.