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CVE-2021-23568

30
FAUCET Score

CVE-2021-23568 describes a critical Prototype Pollution vulnerability in the extend2 package (versions prior to 1.0.1), impacting products like eggjs. This flaw, stemming from an unsafe recursive merge in the extend function, allows for unauthenticated remote attackers to achieve high impact on confidentiality, integrity, and availability. Despite its critical CVSS score of 9.8, there is currently no evidence of active exploitation, publicly available exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.0.1CPE matchmatch criteria
cpe:2.3:a:eggjs:extend2:*:*:*:*:*:node.js:*:*

CVSS Data

CVSS version used by this source: 3.1

7.3HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
LOW
Exploitability Score
3.9
Impact Score
3.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.45%
Probability of exploitation in next 30 days
EPSS Percentile
70.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0145 is in the 57th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
npmpatch availablevia ghsa
Product: extend2Fixed in: 1.0.1

Vendor Advisories (1)

npmGHSA-gjm5-83cw-p3p2high

Prototype Pollution in extend2

Jan 12, 2022

References

github.com / eggjs/extend2/blob/master/index.js%23L50-L60
Broken Link
github.com / eggjs/extend2/commit/aa332a59116c8398976434b57ea477c6823054f8
PatchThird Party Advisory
github.com / eggjs/extend2/pull/2
Issue TrackingPatchThird Party Advisory
snyk.io / vuln/SNYK-JS-EXTEND2-2320315
ExploitThird Party Advisory