CVE-2023-28999

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

Description

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.

Categories

6.9
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.29%
Vendor Advisory github.com Vendor Advisory github.com
Affected: nextcloud security-advisories
Published at:
Updated at:

References

Link Tags
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-8875-wxww-3rr8 vendor advisory
https://github.com/nextcloud/desktop/pull/5560 patch vendor advisory
https://ethz.ch/content/dam/ethz/special-interest/infk/inst-infsec/appliedcrypto/education/theses/report_DanieleCoppola.pdf third party advisory exploit technical description

Frequently Asked Questions

What is the severity of CVE-2023-28999?
CVE-2023-28999 has been scored as a medium severity vulnerability.
How to fix CVE-2023-28999?
To fix CVE-2023-28999, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2023-28999 being actively exploited in the wild?
It is possible that CVE-2023-28999 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2023-28999?
CVE-2023-28999 affects nextcloud security-advisories.
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