7.5
HIGH CVSS 2.0
CVE-2026-6621
1024bit extend-deep index.js prototype pollution
Description

A vulnerability was determined in 1024bit extend-deep up to 0.1.6. The impacted element is an unknown function of the file index.js. This manipulation of the argument __proto__ causes improperly controlled modification of object prototype attributes. Remote exploitation of the attack is possible. The exploit has been publicly disclosed and may be utilized. The code repository of the project has not been active for many years.

INFO

Published Date :

April 20, 2026, 9:16 a.m.

Last Modified :

April 20, 2026, 9:16 a.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-6621 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 HIGH [email protected]
CVSS 3.1 HIGH [email protected]
CVSS 4.0 MEDIUM [email protected]
Solution
Update the vulnerable library or replace it due to lack of maintenance.
  • Update extend-deep to a version without the vulnerability.
  • Remove or replace the vulnerable library.
  • Implement input sanitization and validation.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-6621.

URL Resource
https://github.com/sudo-secure/security-research/blob/main/extend-deep/prototype-pollution/PoC.md
https://vuldb.com/submit/792387
https://vuldb.com/vuln/358256
https://vuldb.com/vuln/358256/cti
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-6621 is associated with the following CWEs:

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-6621 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-6621 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Apr. 20, 2026

    Action Type Old Value New Value
    Added Description A vulnerability was determined in 1024bit extend-deep up to 0.1.6. The impacted element is an unknown function of the file index.js. This manipulation of the argument __proto__ causes improperly controlled modification of object prototype attributes. Remote exploitation of the attack is possible. The exploit has been publicly disclosed and may be utilized. The code repository of the project has not been active for many years.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
    Added CVSS V2 (AV:N/AC:L/Au:N/C:P/I:P/A:P)
    Added CWE CWE-94
    Added CWE CWE-1321
    Added Reference https://github.com/sudo-secure/security-research/blob/main/extend-deep/prototype-pollution/PoC.md
    Added Reference https://vuldb.com/submit/792387
    Added Reference https://vuldb.com/vuln/358256
    Added Reference https://vuldb.com/vuln/358256/cti
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.