CVE-2021-25292 Regular Expression Denial of Service (ReDoS) in Pillow
Attackers can cause a denial of service in Pillow via crafted PDF files triggering catastrophic regex backtracking.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-25292?
CVE-2021-25292 is a medium-severity denial of service vulnerability in Python Pillow, published on 19 Mar 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
An issue was discovered in Pillow before 8.1.1. The PDF parser allows a regular expression DoS (ReDoS) attack via a crafted PDF file because of a catastrophic backtracking regex.
Weakness: CWE-1333
Which versions are affected by CVE-2021-25292?
4 open source packages ship an affected version, including pillow. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
pillow Bitnami | All versions | 8.1.1 |
pillow PyPI | All versions | 8.1.1 |
pillow PyPI | From 5.1.0 | 8.1.1 |
pillow PyPI | From 5.1.0 | 8.1.1 |
Products include Python Pillow.
How do I fix CVE-2021-25292?
Upgrade pillow to 8.1.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-25292 being exploited?
There is no known exploitation of CVE-2021-25292 in the wild and no public exploit code.
Other vulnerabilities in Python Pillow
Sources
Also known as ALPINE-CVE-2021-25292, BIT-pillow-2021-25292, DEBIAN-CVE-2021-25292, GHSA-9hx2-hgq2-2g4f, PYSEC-2021-38, UBUNTU-CVE-2021-25292.