CVE-2021-41170

CVE-2021-41170 is a critical-severity vulnerability in Neoan Neoan3-template with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-732.

Key facts

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.

Frequently asked questions

What is CVE-2021-41170?
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.
How severe is CVE-2021-41170?
CVE-2021-41170 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-41170 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41170?
CVE-2021-41170 affects Neoan Neoan3-template. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-41170?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-41170 published?
CVE-2021-41170 was published on 2021-11-08 and last updated on 2026-06-17.

References

Affected products (1)

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