CVE-2021-32821 Regular expression Denial of Service in MooTools
Attackers can cause denial of service in MooTools by injecting malicious strings into CSS selectors, exploiting a vulnerable regex parser.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-32821?
CVE-2021-32821 is a medium-severity denial of service vulnerability in mootools-core, published on 3 Jan 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
MooTools is a collection of JavaScript utilities for JavaScript developers. All known versions include a CSS selector parser that is vulnerable to Regular Expression Denial of Service (ReDoS). An attack requires that an attacker can inject a string into a CSS selector at runtime, which is quite common with e.g. jQuery CSS selectors. No patches are available for this issue.
Which versions are affected by CVE-2021-32821?
2 open source packages ship an affected version, including mootools. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mootools npm | All versions to 1.5.2 | None |
mootools npm | All versions to 1.5.2 | None |
Products include Mootools Mootools.
How do I fix CVE-2021-32821?
No fix has been published for CVE-2021-32821 yet. Limit exposure of the affected software until one is available.
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-2021-32821 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-32821 exists.
Sources
Also known as DEBIAN-CVE-2021-32821, GHSA-v63q-hgqc-qvpg, UBUNTU-CVE-2021-32821.