How severe is CVE-2020-15227?

CVE-2020-15227 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2020-15227?

CVE-2020-15227 affects the following packages: nette/application (Packagist), nette/application (Packagist), nette/application (Packagist), nette/application (Packagist), nette/application (Packagist), nette/application (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2020-15227?

Update nette/application to 2.2.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-15227 is resolved across your whole dependency graph.

How do I detect CVE-2020-15227 in my Packagist dependencies?

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

How do I mitigate CVE-2020-15227 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2020-15227 actively exploited in the wild?

Yes. There are 2 known exploit references for CVE-2020-15227, 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-2020-15227?

CVE-2020-15227 has an EPSS (Exploit Prediction Scoring System) score of 34.4%, placing it in the 98th 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 warrants monitoring and prompt remediation.

What type of vulnerability is CVE-2020-15227?

CVE-2020-15227 is classified as CWE-74 (CWE-74), Code Injection (CWE-94). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Is there exploit tooling available for CVE-2020-15227?

A Nuclei detection template exists for CVE-2020-15227, 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-2020-15227 published, and has it been updated?

CVE-2020-15227 was published on October 1, 2020 and was last updated on July 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

CRITICAL severity

CVE-2020-15227 — application

CRITICAL

CVE-2020-15227 is a critical-severity (CVSS 9.8) CWE-74 vulnerability in nette/application. 2 public exploit references exist, so weaponization risk is real. A fix is available for nette/application — see the affected versions and patch details below.

Potential Remote Code Execution vulnerability

Also known asGHSA-8gv3-3j7f-wg94

Published

Oct 1, 2020

Updated

Jul 8, 2026

Affected

6 pkgs

Patched

6 / 6

Exploits

2 known

Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

34.4%probability of exploitation in next 30 days

Moderate Risk0.00%

Lower risk than most CVEs98th percentile — riskier than 98% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2020-15227 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

6 pkgs affected

🐘nette/application🐘nette/application🐘nette/application🐘nette/application🐘nette/application🐘nette/application

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Reported by Cyku Hong from DEVCORE (https://devco.re)

Impact

Code injection, possible remote code execution.

Patches

Fixed in nette/application 2.2.10, 2.3.14, 2.4.16, 3.0.6 and nette/nette 2.0.19 and 2.1.13

Affected Packages

6 total 6 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`nette/application`	≥ 2.2.0&&< 2.2.10	2.2.10`composer require nette/application:^2.2.10`
🐘Packagist	`nette/application`	≥ 2.3.0&&< 2.3.14	2.3.14`composer require nette/application:^2.3.14`
🐘Packagist	`nette/application`	≥ 2.4.0&&< 2.4.16	2.4.16`composer require nette/application:^2.4.16`
🐘Packagist	`nette/application`	≥ 3.0.0&&< 3.0.6	3.0.6`composer require nette/application:^3.0.6`
🐘Packagist	`nette/application`	≥ 2.0.0&&< 2.0.19	2.0.19`composer require nette/application:^2.0.19`
🐘Packagist	`nette/application`	≥ 2.1.0&&< 2.1.13	2.1.13`composer require nette/application:^2.1.13`

Affected Products

2 products · 7 configurations

debian linuxdebian

1 version

9.0

Application

applicationnette

≥ 3.0.0 && < 3.0.6

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.

Nette versions before 2.0.19, 2.1.13, 2.2.10, 2.3.14, 2.4.16, 3.0.6 are …

github.comGithubOct 2020

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nette/application, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update nette/application to 2.2.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-15227 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

How to detect CVE-2020-15227

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

nuclei -id cve-2020-15227 -u https://target

Template: Nette Framework - Remote Code Execution
Severity: critical
Impact: Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code on the affected system.
Remediation: Apply the latest security patches provided by the Nette Framework to fix the deserialization vulnerability.

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

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

UbuntuCRITICAL

USN-5983-1Ubuntu

Frequently Asked Questions

Packages nette/application versions prior to 2.2.10, 2.3.14, 2.4.16, 3.0.6 and nette/nette versions prior to 2.0.19 and 2.1.13 are vulnerable to an code injection attack by passing specially formed parameters to URL that may possibly leading to RCE. Reported by Cyku Hong from DEVCORE (https://devco.re) ### Impact Code injection, possible remote code execution. ### Patches Fixed in nette/application 2.2.10, 2.3.14, 2.4.16, 3.0.6 and nette/nette 2.0.19 and 2.1.13

O3 Security · Impact-Aware SCA

Is CVE-2020-15227 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

9.8/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE Classification

CWE-74CWE-74 CWE-94Code Injection

Weaponization

Timeline

Disclosed

Oct 1, 2020

First exploit

Oct 10, 2020

Last updated

Jul 8, 2026

Identifiers

CVE-2020-15227

GHSA-8gv3-3j7f-wg94

References

Advisorygithub.com Advisorylists.debian.org Advisorypackagist.org Advisorypackagist.org Advisorynvd.nist.gov Webblog.nette.org Webgithub.com Packagegithub.com

Related vulnerabilities

This CVE is critical severity — higher than any of the other 8 CVEs with CWE-74 (highest there: high).

GHSA-wwv5-g3v4-889xCVE-2026-55558GHSA-h58c-xccx-75m3CVE-2026-54543GHSA-c7hr-448w-65pxGHSA-jm78-9fvv-mhgrCVE-2026-71320CVE-2026-16729Browse all CWE-74

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedJul 8, 2026

CVE-2020-15227 — application

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Impact

Patches

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

How to detect CVE-2020-15227

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2020-15227 in your dependencies?