CVE-2020-8297Public exploitNetwork attack vector

Authenticated board disclosure via orphaned user ownership

Published Feb 23, 2021 · Updated Aug 4, 2024

IDOR in Nextcloud Deck before 1.0.2 allows remote authenticated users with a reused user identifier to read a deleted user's board data. Deck's user-deletion hook removes assignments and ACL entries but leaves boards owned by the deleted identifier in the database. Recreating an account with that identifier rebinds the orphaned boards to the new user, exposing their contents without write or availability impact.

CVSS severity4.3
Medium
EPSS probability1.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

IDOR in Nextcloud Deck before 1.0.2 allows remote authenticated users with a reused user identifier to read a deleted user's board data. Deck's user-deletion hook removes assignments and ACL entries but leaves boards owned by the deleted identifier in the database. Recreating an account with that identifier rebinds the orphaned boards to the new user, exposing their contents without write or availability impact.

The record

CVE
CVE-2020-8297
Published
Feb 23, 2021
Updated
Aug 4, 2024
Vendor
Nextcloud GmbH
Product
Deck
Classifications
CWE-639, T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=Fixed in 1.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Deckversion=Fixed in 1.0.2

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
4.3NIST NVDCVSS: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 exploitPublished

Weakness, pattern, technique

CWE-639Authorization Bypass Through User-Controlled Key
T1213Data from Information Repositories

Public exploit references

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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