Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learningUpgrade netmask
to version 2.0.1 or higher.
netmask is a library to parse IPv4 CIDR blocks.
Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF). It incorrectly evaluates individual IPv4 octets that contain octal strings as left-stripped integers, leading to an inordinate attack surface on hundreds of thousands of projects that rely on netmask
to filter or evaluate IPv4 block ranges, both inbound and outbound.
For example, a remote unauthenticated attacker can request local resources using input data 0177.0.0.1
(127.0.0.1
), which netmask
evaluates as the public IP 177.0.0.1
.
Contrastingly, a remote authenticated or unauthenticated attacker can input the data 0127.0.0.01
(87.0.0.1
) as localhost, yet the input data is a public IP and can potentially cause local and remote file inclusion (LFI/RFI).
A remote authenticated or unauthenticated attacker can bypass packages that rely on netmask
to filter IP address blocks to reach intranets, VPNs, containers, adjacent VPC instances, or LAN hosts, using input data such as 012.0.0.1
(10.0.0.1
), which netmask
evaluates as 12.0.0.1
(public).
NOTE: This vulnerability has also been identified as: CVE-2021-28918