CVE-2021-39229 : Exploit Details and Defense Strategies

Apprise is an open-source library allowing notifications to various services. An inefficient regular expression in versions below 0.9.5.1 exposes users to a denial of service attack. Find more details below.

Understanding CVE-2021-39229

This section delves into the impact, technical details, and mitigation of the Regular Expression Denial of Service vulnerability in Apprise.

What is CVE-2021-39229?

Apprise users with the IFTTT plugin enabled are vulnerable to a denial of service attack due to an inefficient regular expression.

The Impact of CVE-2021-39229

The vulnerability scores a CVSS base score of 7.5 (High).

Technical Details of CVE-2021-39229

Let's explore specific technical aspects of this vulnerability.

Vulnerability Description

An insecure regular expression in Apprise versions below 0.9.5.1 allows a denial of service attack.

Affected Systems and Versions

Product: Apprise
Vendor: caronc
Versions Affected: < 0.9.5.1

Exploitation Mechanism

The vulnerability can be exploited remotely with low attack complexity, impacting availability severely.

Mitigation and Prevention

Discover the steps to take to mitigate the risks posed by CVE-2021-39229.

Immediate Steps to Take

Upgrade to version 0.9.5.1 to patch the vulnerability.
If unable to upgrade, remove

apprise/plugins/NotifyIFTTT.py

Long-Term Security Practices

Regularly update Apprise and other libraries to prevent future vulnerabilities.

Patching and Updates

Ensure timely application of patches and updates to maintain the security of the application.