Prototype Pollution in Algolia Algoliasearch-Helper

CVE-2025-3193

Versions of the package algoliasearch-helper from 2.0.0-rc1 and before 3.11.2 are vulnerable to Prototype Pollution in the _merge() function in merge.js, which allows constructor.prototype to be written even though doing so throws an error. In the "extreme edge-case" that the resulting error is caught, code injected into the user-supplied search parameter may be exeucted. This is related to but distinct from the issue reported in [CVE-2021-23433](https://security.snyk.io/vuln/SNYK-JS-ALGOLIASEARCHHELPER-1570421). **NOTE:** This vulnerability is not exploitable in the default configuration of InstantSearch since searchParameters are not modifiable by users.

Vulnerability class: Prototype Pollution

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.005 (41.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 41.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-3193: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-3193?
CVE-2025-3193 is a high-severity vulnerability in Algolia Algoliasearch-Helper, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 7.5/10. Published 2025-09-27.
How severe is CVE-2025-3193?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-3193 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.