CVE-2021-23433

Prototype Pollution

5.9 MediumFix available

The package algoliasearch-helper before 3.6.2 are vulnerable to Prototype Pollution due to use of the merge function in src/SearchParameters/index.jsSearchParameters._parseNumbers without any protection against prototype properties. Note that this vulnerability is only exploitable if the implementation allows users to define arbitrary search patterns.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

1.95%Up 1.1 points since Nov 20, 2021

What each source reports

CVE List Score used 5.9

Prototype Pollution

Record: CVE-2021-23433
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P
Updated: 2026-11-02

EUVDEUVD-2021-2399 5.9

Record: EUVD-2021-2399
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P
Updated: 2026-11-03

GitHub AdvisoriesGHSA-vpf5-82c8-9v36 9.8

Prototype Pollution in algoliasearch-helper

Record: GHSA-vpf5-82c8-9v36
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-915, CWE-1321
Updated: 2026-11-02

NVD 5.9

Record: CVE-2021-23433
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0: 6.8 MediumAV:N/AC:M/Au:N/C:P/I:P/A:P
Weakness: CWE-1321
Updated: 2026-11-02

OSV 9.8

Record: CVE-2021-23433
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVGHSA-vpf5-82c8-9v36 9.8

Prototype Pollution in algoliasearch-helper

Record: GHSA-vpf5-82c8-9v36
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-1321, CWE-915
Updated: 2026-11-02

Affected products

algolia algoliasearch-helper

Affected packages

Affected packages
Package	Affected	Fixed
`algoliasearch-helper` npm	before 3.6.2	3.6.2

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, published	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-23433 is a medium vulnerability (CVSS 5.9) in Algolia Algoliasearch-helper, published November 19, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.95%, the 80th percentile. Fixed in algoliasearch-helper 3.6.2.