CVE-2023-28845Network attack vector

Member disclosure via unrestricted participant autocompletion

Published Mar 31, 2023 · Updated Feb 11, 2025

Improper access control in Nextcloud Talk allows remote authenticated users to list members of conversations they have not joined. The participant-autocompletion path returns suggestions drawn from a conversation's member list without first verifying that the requester belongs to that conversation. Affected releases are 14.0.0 through 14.0.8 and 15.0.0 through 15.0.3; a valid account and user interaction are required, and the reported consequence is limited to disclosure of member identities.

CVSS severity3.5
Low
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Nextcloud Talk allows remote authenticated users to list members of conversations they have not joined. The participant-autocompletion path returns suggestions drawn from a conversation's member list without first verifying that the requester belongs to that conversation. Affected releases are 14.0.0 through 14.0.8 and 15.0.0 through 15.0.3; a valid account and user interaction are required, and the reported consequence is limited to disclosure of member identities.

The record

CVE
CVE-2023-28845
Published
Mar 31, 2023
Updated
Feb 11, 2025
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-284, T1087
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 31, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 11, 2025Record 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=>= 14.0.0, < 14.0.9
  2. Affected versionversion=>= 15.0.0, < 15.0.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Security Advisoriesversion=>= 14.0.0, < 14.0.9; version=>= 15.0.0, < 15.0.4

Published CVSS scores

3.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/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-284Improper Access Control
T1087Account Discovery

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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