CVE-2021-28918
CRITICALEPSS 97th pctlDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Exploit Intelligence
Very high risk: more likely to be exploited than 97% of all known CVEs.
References
Related Vulnerabilities
Other CWE-704 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2025-41646 | Critical | 9.8 | 44% | - | Fix |
| CVE-2017-5115 | High | 8.8 | 26% | - | Fix |
| CVE-2018-12453 | High | 7.5 | 24% | - | Fix |
| CVE-2018-3843 | High | 8.8 | 24% | - | - |
| CVE-2017-3106 | High | 8.8 | 22% | - | - |
| CVE-2018-5007 | High | 8.8 | 18% | - | - |
Common questions
How do I fix CVE-2021-28918?
Upgrade netmask to 2.0.1 or later.
Is CVE-2021-28918 being actively exploited?
Not that we know of. CVE-2021-28918 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 16.7% is the estimated probability that it will be exploited in the next 30 days. That is higher than 97% of all scored CVEs.
How severe is CVE-2021-28918?
CVE-2021-28918 has a CVSS v3 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-28918 affect?
Published advisories record a fix for netmask (npm). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2021-28918
Markdown
[](https://tridentstack.com/cve/CVE-2021-28918)HTML
<a href="https://tridentstack.com/cve/CVE-2021-28918"><img src="https://tridentstack.com/cve/badge/CVE-2021-28918.svg" alt="CVE-2021-28918"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.