CVE-2021-25915Public exploitNetwork attack vector

Denial of service via prototype pollution

Published Mar 9, 2021 · Updated Apr 30, 2025

Prototype pollution in Eugene Ware changeset 0.0.1 through 0.2.5 allows attackers to cause denial of service via crafted changes. The apply() function traverses attacker-controlled key arrays without own-property checks and assigns values to proto, modifying Object.prototype. Exploitation requires an application to pass untrusted changes to apply(); polluted properties can crash the process, while code execution requires a reachable gadget.

CVSS severity9.8
Critical
EPSS probability3.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Prototype pollution in Eugene Ware changeset 0.0.1 through 0.2.5 allows attackers to cause denial of service via crafted changes. The apply() function traverses attacker-controlled key arrays without own-property checks and assigns values to proto, modifying Object.prototype. Exploitation requires an application to pass untrusted changes to apply(); polluted properties can crash the process, while code execution requires a reachable gadget.

The record

CVE
CVE-2021-25915
Published
Mar 9, 2021
Updated
Apr 30, 2025
Vendor
Eugene Ware
Product
changeset
Classifications
CWE-1321
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Apr 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.0.1, 0.0.2, 0.0.3, 0.0.4, 0.0.5, 0.0.6, 0.1.0, 0.2.0, 0.2.1, 0.2.3, 0.2.4, 0.2.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Eugene Ware · changesetversion=0.0.1, 0.0.2, 0.0.3, 0.0.4, 0.0.5, 0.0.6, 0.1.0, 0.2.0, 0.2.1, 0.2.3, 0.2.4, 0.2.5

Published CVSS scores

9.8CISA ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo