CVE-2021-39229: Regular expression deinal of service in apprise

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.9% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-09-20 · updated 2026-06-17
Weakness: CWE-400

Description

Apprise is an open source library which allows you to send a notification to almost all of the most popular notification services available. In affected versions users who use Apprise granting them access to the IFTTT plugin (which just comes out of the box) are subject to a denial of service attack on an inefficient regular expression. The vulnerable regular expression is [here](https://github.com/caronc/apprise/blob/0007eade20934ddef0aba38b8f1aad980cfff253/apprise/plugins/NotifyIFTTT.py#L356-L359). The problem has been patched in release version 0.9.5.1. Users who are unable to upgrade are advised to remove `apprise/plugins/NotifyIFTTT.py` to eliminate the service.

Affected products

caronc apprise: before 0.9.5.1 — fixed in 0.9.5.1

How to fix

Upgrade to a fixed version: caronc apprise 0.9.5.1. Check the vendor advisory for mitigations.

References

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