CVE-2024-45614: Puma Puma's Header Normalization Allows For Vulnerability

MODERATE
Advisory Identifier: GHSA-9hf4-67fc-4vf4
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CVSS 5.4
CWE-639 CWE-444
Published
Advisory Summary

CVE-2024-45614 is a MODERATE (CVSS 5.4) puma's header normalization allows for vulnerability (CWE-639: Authorization Bypass Through User-Controlled Key) affecting Puma libraries in the RubyGems ecosystem. The issue involves puma's header normalization allows for client to clobber proxy set headers. Remediation is available by upgrading affected packages to version 5.6.9, 6.4.3.

CVE-2024-45614 at a Glance

CVE Identifier CVE-2024-45614
GHSA Identifier GHSA-9hf4-67fc-4vf4
Severity MODERATE
CVSS v3.1 Base Score 5.4
CWE Classification CWE-639: Authorization Bypass Through User-Controlled Key
Affected Product Puma
Package Ecosystem RubyGems
Published Date
Last Updated

Security Impact

CVSS: 5.4

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

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

How to Fix CVE-2024-45614

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

puma fixed: 5.6.9 
Upgrade puma to 5.6.9
puma fixed: 6.4.3 
Upgrade puma to 6.4.3
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 puma

How to Check if You Are Affected

To determine whether your application is affected by CVE-2024-45614, inspect your project dependencies for Puma:

inspect dependencies for puma

Analyze the terminal output to locate any version of Puma in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.6.9), 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-639: Authorization Bypass Through User-Controlled Key, where the system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. In Puma, 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

### Impact Clients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users trusting headers set by their proxy may be affected. Attackers may be able to downgrade connections to HTTP (non-SSL) or redirect responses, which could cause confidentiality leaks if combined with a separate MITM attack. ### Patches v6.4.3/v5.6.9 now discards any headers using underscores if the non-underscore version also exists. Effectively, allowing the proxy defined headers to always win. ### Workarounds Nginx has a [underscores_in_headers](https://nginx.org/en/docs/http/ngx_http_core_module.html#underscores_in_headers) configuration variable to discard these headers at the proxy level. Any users that are implicitly trusting the proxy defined headers for security or availability should immediately cease doing so until upgraded to the fixed versions.

CVE-2024-45614 Affected Puma Versions

2 component(s)
Fixed Versions:
5.6.96.4.3
Product / Package Ecosystem Affected Versions Fixed Version
puma
gem/puma
RubyGems
< 5.6.9
5.6.9
puma
gem/puma
RubyGems
≥ 6.0.0
< 6.4.3
6.4.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/puma/puma/security/advisories/GHSA-9hf4-67fc-4vf4
NVD — CVE-2024-45614 NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-45614
Security Fix Commit FIX COMMIT
https://github.com/puma/puma/commit/cac3fd18cf29ed43719ff5d52d9cfec215f0a043
Security Fix Commit FIX COMMIT
https://github.com/puma/puma/commit/f196b23be24712fb8fb16051cc124798cc84f70e
Puma Source Repository REPOSITORY
https://github.com/puma/puma
Puma Source Repository REPOSITORY
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/puma/CVE-2024-45614.yml
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2024/11/msg00004.html
nginx.org/en/docs/http/ngx_ht... WEB
https://nginx.org/en/docs/http/ngx_http_core_module.html#underscores_in_headers

Frequently Asked Questions

What is CVE-2024-45614?
CVE-2024-45614 is a security vulnerability in Puma involving Puma's header normalization allows for client to clobber proxy set headers under CWE-639: Authorization Bypass Through User-Controlled Key.
Which Puma versions are affected?
Affected versions include releases prior to 5.6.9, 6.4.3 across affected packages: puma.
What version fixes CVE-2024-45614?
Upgrading to 5.6.9, 6.4.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is puma affected?
Yes, puma is affected in releases prior to 5.6.9, 6.4.3. Upgrade your dependency to 5.6.9, 6.4.3 or later.
What is the CVSS score of CVE-2024-45614?
CVE-2024-45614 has a CVSS v3.1 base score of 5.4 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2024-45614?
CVE-2024-45614 is classified under CWE-639: Authorization Bypass Through User-Controlled Key (The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.).
How can I check RubyGems dependencies for CVE-2024-45614?
Run the dependency tree command: 'inspect dependencies for puma'. 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-9hf4-67fc-4vf4",
  "modified" : "2025-11-04T16:53:06Z",
  "published" : "2024-09-20T14:40:16Z",
  "aliases" : [ "CVE-2024-45614" ],
  "summary" : "Puma's header normalization allows for client to clobber proxy set headers",
  "details" : "### Impact\n\nClients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users trusting headers set by their proxy may be affected. Attackers may be able to downgrade connections to HTTP (non-SSL) or redirect responses, which could cause confidentiality leaks if combined with a separate MITM attack. \n\n### Patches\nv6.4.3/v5.6.9 now discards any headers using underscores if the non-underscore version also exists. Effectively, allowing the proxy defined headers to always win.\n\n### Workarounds\nNginx has a [underscores_in_headers](https://nginx.org/en/docs/http/ngx_http_core_module.html#underscores_in_headers) configuration variable to discard these headers at the proxy level.\n\nAny users that are implicitly trusting the proxy defined headers for security or availability should immediately cease doing so until upgraded to the fixed versions.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "puma"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.6.9"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "puma"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.0.0"
      }, {
        "fixed" : "6.4.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/puma/puma/security/advisories/GHSA-9hf4-67fc-4vf4"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2024-45614"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/puma/puma/commit/cac3fd18cf29ed43719ff5d52d9cfec215f0a043"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/puma/puma/commit/f196b23be24712fb8fb16051cc124798cc84f70e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/puma/puma"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/puma/CVE-2024-45614.yml"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2024/11/msg00004.html"
  }, {
    "type" : "WEB",
    "url" : "https://nginx.org/en/docs/http/ngx_http_core_module.html#underscores_in_headers"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-444", "CWE-639" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-09-20T14:40:16Z",
    "nvd_published_at" : "2024-09-19T23:15:11Z"
  }
}