How severe is CVE-2020-15256?

CVE-2020-15256 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2020-15256?

CVE-2020-15256 affects the following packages: object-path (npm). Ecosystems affected: npm.

How do I fix CVE-2020-15256?

Update object-path to 0.11.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-15256 is resolved across your whole dependency graph.

How do I detect CVE-2020-15256 in my npm dependencies?

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

How do I mitigate CVE-2020-15256 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-2020-15256 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-15256 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-15256?

CVE-2020-15256 has an EPSS (Exploit Prediction Scoring System) score of 1.5%, placing it in the 74th 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-2020-15256?

CVE-2020-15256 is classified as Improper Input Validation (CWE-20), CWE-471 (CWE-471). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2020-15256 published, and has it been updated?

CVE-2020-15256 was published on October 19, 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.

📦

📦 npm

Not in CISA KEV

CRITICAL severity

CVE-2020-15256 — object-path

CRITICALFix: mariocasciaro/object-path@2be3354

CVE-2020-15256 is a critical-severity (CVSS 9.8) Improper Input Validation vulnerability in object-path. A fix is available for object-path — see the affected versions and patch details below.

Prototype pollution in object-path

Also known asGHSA-cwx2-736x-mf6w

Published

Oct 19, 2020

Updated

Jul 8, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs74th percentile — riskier than 74% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2020-15256 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 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.

2Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

object-pathnpm

3.2Mdownloads / week

Description

Impact

A prototype pollution vulnerability has been found in object-path <= 0.11.4 affecting the set() method. The vulnerability is limited to the includeInheritedProps mode (if version >= 0.11.0 is used), which has to be explicitly enabled by creating a new instance of object-path and setting the option includeInheritedProps: true, or by using the default withInheritedProps instance. The default operating mode is not affected by the vulnerability if version >= 0.11.0 is used. Any usage of set() in versions < 0.11.0 is vulnerable.

Patches

Upgrade to version >= 0.11.5

Workarounds

Don't use the includeInheritedProps: true options or the withInheritedProps instance if using a version >= 0.11.0.

References

For more information

If you have any questions or comments about this advisory:

Open an issue in object-path

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`object-path`	all versions	0.11.5`npm install object-path@0.11.5`

Affected Products

1 product · 1 configurations

Application

object-pathobject-path_project

< 0.11.5

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for object-path, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update object-path to 0.11.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-15256 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.

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.

Red HatImportant

Red Hat Advanced Cluster Management for Kubernetes 2.1 uses an affected version of object-path, but the vulnerable functionality `includeInheritedProps` and `withInheritedProps` is not present. A future update will include fixed versions of object-path, which will prevent this vulnerability being introduced.

Workaround published by Red Hat

Projects using object-path versions 0.11.0 through 0.11.4 are only exposed to this vulnerability if they use the setting `includeInheritedProps: true` or use the `withInheritedProps` instance. If you are using these versions but this setting and class are both absent from your code, the vulnerability can not be exploited.

Source: Red Hat security advisory for CVE-2020-15256 (CC BY 4.0)

UbuntuCRITICAL

USN-5967-1Ubuntu

Frequently Asked Questions

### Impact A prototype pollution vulnerability has been found in `object-path` <= 0.11.4 affecting the `set()` method. The vulnerability is limited to the `includeInheritedProps` mode (if version >= 0.11.0 is used), which has to be explicitly enabled by creating a new instance of `object-path` and setting the option `includeInheritedProps: true`, or by using the default `withInheritedProps` instance. The default operating mode is not affected by the vulnerability if version >= 0.11.0 is used. Any usage of `set()` in versions < 0.11.0 is vulnerable. ### Patches Upgrade to version >= 0.11.5 #