How severe is CVE-2021-41097?

CVE-2021-41097 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-41097?

CVE-2021-41097 affects the following packages: aurelia-path (npm). Ecosystems affected: npm.

How do I fix CVE-2021-41097?

Update aurelia-path to 1.1.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41097 is resolved across your whole dependency graph.

How do I detect CVE-2021-41097 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aurelia-path, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-41097 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2021-41097 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2021-41097, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-41097?

CVE-2021-41097 has an EPSS (Exploit Prediction Scoring System) score of 4.9%, placing it in the 92th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-41097?

CVE-2021-41097 is classified as CWE-1321 (CWE-1321). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2021-41097?

A Nuclei detection template exists for CVE-2021-41097, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-41097 published, and has it been updated?

CVE-2021-41097 was published on September 27, 2021 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

HIGH severity

CVE-2021-41097 — aurelia-path

HIGHFix: aurelia/path@7c4e235

CVE-2021-41097 is a high-severity (CVSS 7.5) CWE-1321 vulnerability in aurelia-path. 1 public exploit reference exists, so weaponization risk is real. A fix is available for aurelia-path — see the affected versions and patch details below.

Prototype pollution in aurelia-path

Also known asGHSA-3c9c-2p65-qvwv

Published

Sep 27, 2021

Updated

Jul 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Sep 30, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

4.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs92th percentile — riskier than 92% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-41097 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

50other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

aurelia-pathnpm

24Kdownloads / week

Description

Impact

The vulnerability exposes Aurelia application that uses aurelia-path package to parse a string. The majority of this will be Aurelia applications that employ the aurelia-router package. An example is this could allow an attacker to change the prototype of base object class Object by tricking an application to parse the following URL: https://aurelia.io/blog/?__proto__[asdf]=asdf

Patches

The problem should be patched in version 1.1.7. Any version earlier than this is vulnerable.

Workarounds

A partial work around is to free the Object prototype:

Object.freeze(Object.prototype)

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`aurelia-path`	all versions	1.1.7`npm install aurelia-path@1.1.7`

Affected Products

1 product · 1 configurations

Application

aurelia-pathbluespire

< 1.1.7

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

aurelia-path is part of the Aurelia platform and contains utilities for …

github.comNVDOct 2021

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aurelia-path, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update aurelia-path to 1.1.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41097 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How to detect CVE-2021-41097

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2021-41097 -u https://target

Template: Aurelia-Path < 1.1.7 - Prototype Pollution
Severity: high
Impact: Update to version 1.1.7 or later.
Remediation: Aurelia-path parseQueryString function was found vulnerable to prototype pollution via crafted __proto__ URL parameters.

Template by ProjectDiscovery nuclei-templates (0x_Akoko), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

### Impact The vulnerability exposes Aurelia application that uses `aurelia-path` package to parse a string. The majority of this will be Aurelia applications that employ the `aurelia-router` package. An example is this could allow an attacker to change the prototype of base object class `Object` by tricking an application to parse the following URL: `https://aurelia.io/blog/?__proto__[asdf]=asdf` ### Patches The problem should be patched in version `1.1.7`. Any version earlier than this is vulnerable. ### Workarounds A partial work around is to free the Object prototype: ```ts Object.freeze