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Nextcloud ServerApplication · Nextcloud

CVE-2023-28643

HIGH · 8.8 CVSS v3.1 Published 2023-03-30
Fix available
A fix is available. Upgrade to 24.0.9 / 25.0.3 or later.
See remediation →
94/100
Remediation priority · Urgent
Public exploit Remotely reachable Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Nextcloud server is an open source home cloud implementation. In affected versions when a recipient receives 2 shares with the same name, while a memory cache is configured, the second share will replace the first one instead of being renamed to `{name} (2)`. It is recommended that the Nextcloud Server is upgraded to 25.0.3 or 24.0.9. Users unable to upgrade should avoid sharing 2 folders with the same name to the same user.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Nextcloud ServerApplication
Affected:>= 24.0.0, < 24.0.9>= 25.0.0, < 25.0.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 24.0.9 / 25.0.3 or later
Fixed in 24.0.925.0.3
Vendor patch github.com →
Recommended fix High confidence

24.0.9 or 25.0.3

  1. Backup the Nextcloud data directory and database before upgrading
  2. Ensure the system meets the requirements for Nextcloud 24.0.9 or 25.0.3
  3. Place Nextcloud in maintenance mode: occ maintenance:mode --on
  4. For package-based installations: update the package repository and run apt update && apt upgrade (or yum update)
  5. Alternatively, download Nextcloud 24.0.9 or 25.0.3 from the official Nextcloud website and extract to the web server directory
  6. Run occ upgrade after files are updated
  7. Disable maintenance mode: occ maintenance:mode --off
  8. Verify the upgrade was successful by logging in and checking the admin panel shows the new version
Caveat Standard Nextcloud upgrade risks apply - test in staging first; review breaking changes between 24.x and 25.x releases

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,950. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-28643 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data