CVE-2021-23351: Github.com/pires/go proxyproto Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-fqh4-rh59-xhvf
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CVSS 4.9
CWE-400
Published
Advisory Summary

CVE-2021-23351 is a MODERATE (CVSS 4.9) denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Github.com/pires/go proxyproto libraries in the Go ecosystem. The issue involves github.com/pires/go-proxyproto denial of service vulnerability. Remediation is available by upgrading affected packages to version 0.5.0.

CVE-2021-23351 at a Glance

CVE Identifier CVE-2021-23351
GHSA Identifier GHSA-fqh4-rh59-xhvf
Severity MODERATE
CVSS v3.1 Base Score 4.9
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Github.com/pires/go proxyproto
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 4.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required High (PR:H)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2021-23351

To remediate this vulnerability, upgrade all affected Github.com/pires/go proxyproto dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/pires/go-proxyproto fixed: 0.5.0 
Upgrade github.com/pires/go-proxyproto to 0.5.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/pires/go-proxyproto

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-23351, inspect your project dependencies for Github.com/pires/go proxyproto:

inspect dependencies for github.com/pires/go-proxyproto

Analyze the terminal output to locate any version of Github.com/pires/go proxyproto in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.5.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Github.com/pires/go proxyproto, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

The package `github.com/pires/go-proxyproto` before 0.5.0 are vulnerable to Denial of Service (DoS) via the `parseVersion1()` function. The reader in this package is a default `bufio.Reader` wrapping a `net.Conn`. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.

CVE-2021-23351 Affected Github.com/pires/go proxyproto Versions

1 component(s)
Fixed Versions:
0.5.0
Product / Package Ecosystem Affected Versions Fixed Version
github.com/pires/go-proxyproto
golang/github.com/pires/go-proxyproto
Go
< 0.5.0
0.5.0

References

NVD — CVE-2021-23351 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-23351
Github.com/pires/go proxyproto Source Repository REPOSITORY
https://github.com/pires/go-proxyproto/issues/69
Github.com/pires/go proxyproto Source Repository REPOSITORY
https://github.com/pires/go-proxyproto/pull/71
Security Fix Commit FIX COMMIT
https://github.com/pires/go-proxyproto/commit/7f48261db810703d173f27f3309a808cc2b49b8b
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4BNVGJMVI3ZTZ675EFPUHPGXCKCGSX46
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/C36IBVOZXRTWM7MGTRUTOM56P5RR74VU
snyk.io/vuln/snyk-golang-gi... WEB
https://snyk.io/vuln/SNYK-GOLANG-GITHUBCOMPIRESGOPROXYPROTO-1081577

Frequently Asked Questions

What is CVE-2021-23351?
CVE-2021-23351 is a security vulnerability in Github.com/pires/go proxyproto involving github.com/pires/go-proxyproto denial of service vulnerability under CWE-400: Uncontrolled Resource Consumption.
Which Github.com/pires/go proxyproto versions are affected?
Affected versions include releases prior to 0.5.0 across affected packages: github.com/pires/go-proxyproto.
What version fixes CVE-2021-23351?
Upgrading to 0.5.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/pires/go-proxyproto affected?
Yes, github.com/pires/go-proxyproto is affected in releases prior to 0.5.0. Upgrade your dependency to 0.5.0 or later.
What is the CVSS score of CVE-2021-23351?
CVE-2021-23351 has a CVSS v3.1 base score of 4.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2021-23351?
CVE-2021-23351 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check Go dependencies for CVE-2021-23351?
Run the dependency tree command: 'inspect dependencies for github.com/pires/go-proxyproto'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-fqh4-rh59-xhvf",
  "modified" : "2023-09-14T19:22:34Z",
  "published" : "2021-05-18T21:07:43Z",
  "aliases" : [ "CVE-2021-23351" ],
  "summary" : "github.com/pires/go-proxyproto denial of service vulnerability",
  "details" : "The package `github.com/pires/go-proxyproto` before 0.5.0 are vulnerable to Denial of Service (DoS) via the `parseVersion1()` function. The reader in this package is a default `bufio.Reader` wrapping a `net.Conn`. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/pires/go-proxyproto"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.5.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-23351"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pires/go-proxyproto/issues/69"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pires/go-proxyproto/pull/71"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pires/go-proxyproto/commit/7f48261db810703d173f27f3309a808cc2b49b8b"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4BNVGJMVI3ZTZ675EFPUHPGXCKCGSX46"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/C36IBVOZXRTWM7MGTRUTOM56P5RR74VU"
  }, {
    "type" : "WEB",
    "url" : "https://snyk.io/vuln/SNYK-GOLANG-GITHUBCOMPIRESGOPROXYPROTO-1081577"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-18T21:03:39Z",
    "nvd_published_at" : null
  }
}