CVE-2021-23370Network attack vector

Object prototype modification via unsafe recursive merge

Published Apr 12, 2021 · Updated Sep 17, 2024

Prototype pollution in Swiper before 6.5.1 allows remote attackers to modify inherited JavaScript object properties via crafted input. The extend helpers recursively copy source keys into target objects without excluding proto, constructor, and prototype keys. Exploitation requires a consuming application to pass attacker-controlled object keys into a helper; downstream impact depends on how inherited properties are used.

CVSS severity9.8
Critical
EPSS probability2.20%
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 Swiper before 6.5.1 allows remote attackers to modify inherited JavaScript object properties via crafted input. The extend helpers recursively copy source keys into target objects without excluding proto, constructor, and prototype keys. Exploitation requires a consuming application to pass attacker-controlled object keys into a helper; downstream impact depends on how inherited properties are used.

The record

CVE
CVE-2021-23370
Published
Apr 12, 2021
Updated
Sep 17, 2024
Vendor
NOLIMITS4WEB LLC
Product
Swiper
Classifications
CWE-1321
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record 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=unspecified <6.5.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NOLIMITS4WEB LLC · Swiperversion=unspecified <6.5.1

Published CVSS scores

9.8GitHub Advisory DatabaseCVSS: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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