CVE-2021-41170 Evaluation of closures can lead to execution of methods & functions in current program scope
Attackers can execute arbitrary methods or functions in the current program scope by passing malicious closures to the template engine.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-41170?
CVE-2021-41170 is a critical code injection vulnerability in sroehrl neoan3-template, published on 8 Nov 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
neoan3-apps/template is a neoan3 minimal template engine. Versions prior to 1.1.1 have allowed for passing in closures directly into the template engine. As a result values that are callable are executed by the template engine. The issue arises if a value has the same name as a method or function in scope and can therefore be executed either by mistake or maliciously. In theory all users of the package are affected as long as they either deal with direct user input or database values. A multi-step attack on is therefore plausible. Version 1.1.1 has addressed this vulnerability. Unfortunately only working with hardcoded values is safe in prior versions. As this likely defeats the purpose of a template engine, please upgrade.
Which versions are affected by CVE-2021-41170?
2 open source packages ship an affected version, including neoan3-apps/template. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
neoan3-apps/template Packagist | All versions | 1.1.1 |
neoan3-apps/template Packagist | All versions | 1.1.1 |
Products include Neoan Neoan3-Template.
How do I fix CVE-2021-41170?
Upgrade neoan3-apps/template to 1.1.1 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2021-41170 being exploited?
There is no known exploitation of CVE-2021-41170 in the wild and no public exploit code.
Sources
Also known as GHSA-3v56-q6r6-4gcw.