CVE-2021-25941Network attack vector

Application disruption via prototype-key merging

Published May 14, 2021 · Updated Apr 30, 2025

Prototype pollution in ASaiAnudeep deep-override 1.0.0 through 1.0.1 allows remote attackers to disrupt consuming applications via crafted objects. The override function recursively copies source keys without rejecting proto, constructor, or prototype, allowing changes to inherited object properties. An application must pass attacker-controlled objects into the function; subsequent use of polluted properties determines whether execution ends in an exception or attacker-influenced code execution.

CVSS severity9.8
Critical
EPSS probability3.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Prototype pollution in ASaiAnudeep deep-override 1.0.0 through 1.0.1 allows remote attackers to disrupt consuming applications via crafted objects. The override function recursively copies source keys without rejecting proto, constructor, or prototype, allowing changes to inherited object properties. An application must pass attacker-controlled objects into the function; subsequent use of polluted properties determines whether execution ends in an exception or attacker-influenced code execution.

The record

CVE
CVE-2021-25941
Published
May 14, 2021
Updated
Apr 30, 2025
Vendor
ASaiAnudeep
Product
deep-override
Classifications
CWE-1321
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 14, 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

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Is a vulnerable build present?

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

  1. Affected versionversion=1.0.0, 1.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ASaiAnudeep · deep-overrideversion=1.0.0, 1.0.1

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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