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GHSA-656c-6cxf-hvcv

MediumCVSS 4.2 / 10
Published Jun 18, 2021·Last modified Feb 16, 2024
Affected Components(0)

No affected components available

Description

Flask-Cache adds easy cache support to Flask. 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.

However, this is not a high-severity issue, as for an attack like this to work, an attacker must:

  1. Be able to write arbitrary values to the cache
  2. Be able to generate a cache key that will collide with a value being read by the application
  3. Cause the application to read a maliciously-injected value

Any situation where all 3 of those is true is a situation where the application has larger problems; for example, if someone's able to inject malicious cached rendered pages into a Flask app's cache, then they can make the website say literally anything they want, regardless of whether it involves the execution of remote code. Basically, the Pickle vulnerability follows from a website already being extremely vulnerable (due to conditions 1 and 2 being met).

Risk Scores
Base Score
4.2

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker needs high-level or administrative privileges. The attacker needs the user to perform some action, like clicking a link. The impact is confined to the system where the vulnerability exists. There is a high impact on the integrity of the data.

Threat Intelligence
3.9

Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.

EPSS
7.29%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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