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Nextcloud ServerApplication · Nextcloud

CVE-2023-25818

HIGH · 7.1 CVSS v3.1 Published 2023-03-27
Fix available
A fix is available. Upgrade to 21.0.9.10 / 22.2.10.10 or later.
See remediation →
77/100
Remediation priority · High
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, personal cloud implementation. In affected versions a malicious user could try to reset the password of another user and then brute force the 62^21 combinations for the password reset token. As of commit `704eb3aa` password reset attempts are now throttled. Note that 62^21 combinations would significant compute resources to brute force. None the less it is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. There are no known workarounds for this vulnerability.

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:>= 21.0.0, < 21.0.9.10>= 22.0.0, < 22.2.10.10>= 23.0.0, < 23.0.12.5>= 24.0.0, < 24.0.10>= 25.0.0, < 25.0.4

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
Low
Integrity
High
Availability
None

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

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 21.0.9.10 / 22.2.10.10 / 23.0.12.5 or later
Fixed in 21.0.9.1022.2.10.1023.0.12.5
Vendor patch github.com →
Recommended fix High confidence

Nextcloud Server 25.0.4 (or 24.0.10 for the LTS branch)

  1. 1. Create a complete backup of the Nextcloud data directory, database, and config.php file.
  2. 2. Stop the web server (e.g., Apache, Nginx) to prevent changes during upgrade.
  3. 3. Download Nextcloud Server version 25.0.4 (the recommended stable release) from the official Nextcloud website.
  4. 4. Extract the new Nextcloud package to a temporary location.
  5. 5. Copy the 'occ' command-line tool from the new package to your Nextcloud installation directory.
  6. 6. Replace the existing Nextcloud files with the new version files, preserving the config/ and data/ directories.
  7. 7. Set correct ownership on all files (typically www-data for Apache).
  8. 8. Restart the web server.
Caveat Major version upgrades in Nextcloud may introduce breaking changes; review the Nextcloud changelog before upgrading across major versions (e.g., 24.x to 25.x)

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-2023-25818 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
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