CVE-2021-28918

Name: CVE-2021-28918
Creator: NVD / NIST
Published: 2021-04-01T13:15:14.46+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 16.36%

Last modified Jun 17, 2026

CVE-2021-28918 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. Improper input validation of octal strings in netmask npm package v1.0.6 and below allows unauthenticated remote attackers to perform indeterminate SSRF, RFI, and LFI attacks on many of the dependent packages. A remote unauthenticated attacker can bypass packages relying on netmask to filter IPs and reach critical VPN or LAN hosts.. EPSS estimates a 16.36% chance of exploitation in the next 30 days.

Description

Improper input validation of octal strings in netmask npm package v1.0.6 and below allows unauthenticated remote attackers to perform indeterminate SSRF, RFI, and LFI attacks on many of the dependent packages. A remote unauthenticated attacker can bypass packages relying on netmask to filter IPs and reach critical VPN or LAN hosts.

Metrics

CVSS 3.1

9.1/10

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

EPSS Probability

16.36%

96.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-704

Affected Software

Vendor	Product	Versions
Netmask Project	Netmask	<= 1.0.6

References

https://github.com/advisories/GHSA-pch5-whg9-qr2rThird Party Advisory
https://github.com/rs/node-netmaskThird Party Advisory
https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-011.mdExploit, Third Party Advisory
https://rootdaemon.com/2021/03/29/vulnerability-in-netmask-npm-package-affects-280000-projects/Third Party Advisory
https://security.netapp.com/advisory/ntap-20210528-0010/Third Party Advisory
https://www.bleepingcomputer.com/news/security/critical-netmask-networking-bug-impacts-thousands-of-applications/Exploit, Press/Media Coverage, Third Party Advisory
https://www.npmjs.com/package/netmaskProduct, Third Party Advisory
https://github.com/advisories/GHSA-pch5-whg9-qr2rThird Party Advisory
https://github.com/rs/node-netmaskThird Party Advisory
https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-011.mdExploit, Third Party Advisory
https://rootdaemon.com/2021/03/29/vulnerability-in-netmask-npm-package-affects-280000-projects/Third Party Advisory
https://security.netapp.com/advisory/ntap-20210528-0010/Third Party Advisory
https://www.bleepingcomputer.com/news/security/critical-netmask-networking-bug-impacts-thousands-of-applications/Exploit, Press/Media Coverage, Third Party Advisory
https://www.npmjs.com/package/netmaskProduct, Third Party Advisory

Timeline

Published: Apr 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-28918?

How severe is CVE-2021-28918?

CVE-2021-28918 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 16.36% probability of exploitation in the next 30 days.

How do I fix CVE-2021-28918?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-28918?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST