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🛡️ CVE-2023-28999 — desktop

🟡 CVSS 6.9 — Medium ⚠️ Exploit Public CWE-325 NVD
6.9
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Nextcloud: Lack of authenticity of metadata keys allows a malicious server to gain access to E2EE folders

Nextcloud is an open-source productivity platform. In Nextcloud Desktop client 3.0.0 until 3.8.0, Nextcloud Android app 3.13.0 until 3.25.0, and Nextcloud iOS app 3.0.5 until 4.8.0, a malicious server administrator can gain full access to an end-to-end encrypted folder. They can decrypt files, recover the folder structure and add new files.​ This issue is fixed in Nextcloud Desktop 3.8.0, Nextcloud Android 3.25.0, and Nextcloud iOS 4.8.0. No known workarounds are available.

How this vulnerability can be exploited

This issue can be reached with physical access to the device, attack complexity is low, an attacker needs administrative privileges on the target. A user must be tricked into taking some action. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity high, availability low.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:L

  • Attack vector: Physical — the attacker has to touch the device.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: High — administrative rights are needed first.
  • User interaction: Required — someone has to click, open or visit something.
  • Scope: Changed — a successful attack reaches components beyond the vulnerable one.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: Low — limited, and the attacker does not choose what is affected.

Weakness class

CVE-2023-28999 is classified as CWE-325: Missing Cryptographic Step. A required step of a cryptographic algorithm is skipped, weakening the guarantees it should provide.

Affected software

CVE-2023-28999 is recorded against 2 packages.

  • desktop (from 3.0.0 up to 3.8.0)
  • nextcloud

Timeline and source

Published on 4 April 2023 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. A vendor advisory or fix has been published. Record sourced from NVD.

References

ethz.ch
github.com
github.com
ethz.ch
github.com
github.com

Other advisories for this package

desktop has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-325: Missing Cryptographic Step) in other software:

CVE-2023-28999 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity MEDIUM
CVSS Score 6.9
CVSS Vector CVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:L
CWE CWE-325
Public Exploit ⚠️ Yes
Source NVD
Published 2023-04-04
Updated 2026-08-20
Modified 2026-06-17

Affected Packages

Software From version Fixed in
desktop 3.0.0 3.8.0
nextcloud — —

Similar Threats

Exploit Protection

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CVE-2023-28999 carries CVSS 6.9 Medium rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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