CVE-2021-32788Network attack vector

Whisper-author disclosure via topic metadata

Published Jul 27, 2021 · Updated Aug 3, 2024

Information disclosure in Discourse before 2.7.7 allows remote authenticated users to identify whisper-post creators through topic metadata. PostCreator#ensure_in_allowed_users adds a whisper author to a private message's allowed-user list, while PostDestroyer#make_previous_post_the_last_one can choose a whisper author as the topic's last poster. Whispers must be enabled, and exposure reaches non-staff message participants when staff create a whisper or when the post following one is deleted.

CVSS severity4.3
Medium
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Discourse before 2.7.7 allows remote authenticated users to identify whisper-post creators through topic metadata. PostCreator#ensure_in_allowed_users adds a whisper author to a private message's allowed-user list, while PostDestroyer#make_previous_post_the_last_one can choose a whisper author as the topic's last poster. Whispers must be enabled, and exposure reaches non-staff message participants when staff create a whisper or when the post following one is deleted.

The record

CVE
CVE-2021-32788
Published
Jul 27, 2021
Updated
Aug 3, 2024
Vendor
Discourse
Product
Discourse
Classifications
CWE-402, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 27, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.7.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Discourse · Discourseversion=< 2.7.7

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
4.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-402Transmission of Private Resources into a New Sphere ('Resource Leak')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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