What is CVE-2023-26135?

CVE-2023-26135 is a high-severity vulnerability in Flatnest Project, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 7.3/10. Published 2023-06-30.

How severe is CVE-2023-26135?

High severity. CVSS v3 base score is 7.3 out of 10.

Prototype Pollution in Flatnest Project

CVE-2023-26135

All versions of the package flatnest are vulnerable to Prototype Pollution via the nest() function in the flatnest/nest.js file.

Vulnerability class: Prototype Pollution

Published 2023-06-30 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.009 (59.1th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 59th percentile — 59.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Flatnest Project
Flatnest — versions 0

Weakness classification (CWE)

CWE-1321 — Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution)

References

security.snyk.io/vuln/SNYK-JS-FLATNEST-3185149 (Exploit, Third Party Advisory)
github.com/brycebaril/node-flatnest/issues/4 (Exploit, Issue Tracking)
github.com/brycebaril/node-flatnest/blob/b7d97ec64a04632378db87fcf3577bd51ac3ee… (Broken Link)
github.com/brycebaril/node-flatnest/commit/27d569baf9d9d25677640edeaf2d13af1658…

Frequently asked questions

What is CVE-2023-26135?: CVE-2023-26135 is a high-severity vulnerability in Flatnest Project, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 7.3/10. Published 2023-06-30.
How severe is CVE-2023-26135?: High severity. CVSS v3 base score is 7.3 out of 10.