CVE-2021-33026

CRITICAL

Flask-Caching <1.10.1 - Code Injection

Title source: llm

Description

The Flask-Caching extension through 1.10.1 for Flask relies on Pickle for serialization, which may lead to remote code execution or local privilege escalation. If an attacker gains access to cache storage (e.g., filesystem, Memcached, Redis, etc.), they can construct a crafted payload, poison the cache, and execute Python code. NOTE: a third party indicates that exploitation is extremely unlikely unless the machine is already compromised; in other cases, the attacker would be unable to write their payload to the cache and generate the required collision

Exploits (2)

nomisec WORKING POC 4 stars
by CarlosG13 · poc
https://github.com/CarlosG13/CVE-2021-33026
nomisec WORKING POC 1 stars
by Agilevatester · poc
https://github.com/Agilevatester/FlaskCache_CVE-2021-33026_POC

Scores

CVSS v3 9.8
EPSS 0.1628
EPSS Percentile 94.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Classification

CWE
CWE-502
Status published

Affected Products (2)

flask-caching_project/flask-caching < 1.10.1
pypi/Flask-Caching PyPI

Timeline

Published May 13, 2021
Tracked Since Feb 18, 2026