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Fencer Vulns
high 7.5

CVE-2021-39229 json

Regular expression deinal of service in apprise

published 2021-09-20 5 y ago modified 2026-07-08 4 mo ago also GHSA-qhmp-h54x-38qr , PYSEC-2021-327 , EUVD-2021-0025

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi apprise 0.9.5.1
  • nuxref apprise 0.9.5.1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-39229 updated cvss 7.5

python-apprise: inefficient regular expression may lead to DoS

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.89% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/caronc/apprise/blob/0007eade20934ddef0aba38b8f1aad980cfff253/apprise/plugins/NotifyIFTTT.py#L356-L359 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi apprise
<0.9.5.1
0.9.5.1

Affected products

  • caronc apprise

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.