Nextcloud Calendar app: DoS via oversized email validation (pre4.4.4)
CVE-2023-45150 Published on October 16, 2023
Inviting excessive long email addresses to a calendar event makes the Nextcloud server unresponsive
Nextcloud calendar is a calendar app for the Nextcloud server platform. Due to missing precondition checks the server was trying to validate strings of any length as email addresses even when megabytes of data were provided, eventually making the server busy and unresponsive. It is recommended that the Nextcloud Calendar app is upgraded to 4.4.4. The only workaround for users unable to upgrade is to disable the calendar app.
Vulnerability Analysis
CVE-2023-45150 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2023-45150. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.
Weakness Type
What is a Resource Exhaustion Vulnerability?
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
CVE-2023-45150 has been classified to as a Resource Exhaustion vulnerability or weakness.
Products Associated with CVE-2023-45150
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Affected Versions
nextcloud security-advisories:- Version >= 1.0.0, < 4.4.4 is affected.
- Version 1.0.0 and below 4.4.4 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.