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CVE-2021-30477

MEDIUMCVSS 4.3/10EPSS 0.66%

Last modified

CVE-2021-30477 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. 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.. EPSS estimates a 0.66% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
4.3/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS Probability
0.66%

46.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersions
ZulipZulip Server< 3.4

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is 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 send messages to private streams that the user was not intended to be able to send messages to.
How severe is CVE-2021-30477?
CVE-2021-30477 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.66% probability of exploitation in the next 30 days.
How do I fix CVE-2021-30477?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-30477?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST