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Vulnerability record · CVE-2021-28918 · published 1 April 2021

CVE-2021-28918: Netmask project netmask vulnerability

Netmask Project · Netmask

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.

9.1 CVSS 3.1 Critical EPSS 17% · top 3.1% CWE-704 · CWE-704
9.1CVSS 3.1 base score, v2 6.4
17%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
14References, 4 tagged exploit
17 Jun 2026Last modified by NVD

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.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/advisories/GHSA-pch5-whg9-qr2r Third Party Advisory
https://github.com/rs/node-netmask Third Party Advisory
https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-011.md ExploitThird 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/ ExploitPress/Media CoverageThird Party Advisory
https://www.npmjs.com/package/netmask ProductThird Party Advisory
https://github.com/advisories/GHSA-pch5-whg9-qr2r Third Party Advisory
https://github.com/rs/node-netmask Third Party Advisory
https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-011.md ExploitThird 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/ ExploitPress/Media CoverageThird Party Advisory
https://www.npmjs.com/package/netmask ProductThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

5.3CVE-2021-29418Netmask project netmask improper input validation vulnerabilityThe netmask package before 2.0.1 for Node.js mishandles certain unexpected characters in an IP address string, such as an octal digit of 9. This (in …EPSS 1.7%

Source: NIST National Vulnerability Database (record CVE-2021-28918), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.