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TI-2020-08951 Aliases CVE-2020-11077GHSA-w64w-qqph-5gxm

HTTP Smuggling via Transfer-Encoding Header in Puma

Priority LOW 38CWE-444Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Partial Red Hat: 2 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA, GitHub and Red Hat.

Summary

In Puma (RubyGem) before 4.3.5 and 3.12.6, a client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client. If the proxy uses persistent connections and the client adds another request in via HTTP pipelining, the proxy may mistake it as the first request's body. Puma, however, would see it as two requests, and when processing the second request, send back a response that the proxy does not expect. If the proxy has reused the persistent connection to Puma to send another request for a different client, the second response from the first client will be sent to the second client. This is a similar but different vulnerability from CVE-2020-11076. The problem has been fixed in Puma 3.12.6 and Puma 4.3.5.

Why it matters now

EPSS 0.02877 86th percentileScored 2026-11-07
Fix Partial puma (puma): 3.12.6, 4.3.5puma (RubyGems): 3.12.6, 4.3.5Red Hat: 2 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
pumapumabefore 3.12.6; 4.0.0 to before 4.3.53.12.6, 4.3.5Patch availableCNA
—puma (RubyGems)before 3.12.63.12.6Patch availableGHSA-w64w-qqph-5gxm
—puma (RubyGems)4.0.0 to before 4.3.54.3.5Patch availableGHSA-w64w-qqph-5gxm
  • puma Vendorpuma Affected before 3.12.6; 4.0.0 to before 4.3.5 Fixed in 3.12.6, 4.3.5 Patch available CNA
  • puma (RubyGems) Vendor— Affected before 3.12.6 Fixed in 3.12.6 Patch available GHSA-w64w-qqph-5gxm
  • puma (RubyGems) Vendor— Affected 4.0.0 to before 4.3.5 Fixed in 4.3.5 Patch available GHSA-w64w-qqph-5gxm

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:*3.0.0 to before 3.12.6; 4.0.0 to before 4.3.5Vulnerablepuma
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*33VulnerableFedoraproject
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*9.0VulnerableDebian
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*15.1VulnerableopenSUSE
cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*15.2VulnerableopenSUSE
  • cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:* Versions 3.0.0 to before 3.12.6; 4.0.0 to before 4.3.5 Vulnerable ·puma
  • cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
  • cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
  • cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:* Versions 15.1 Vulnerable ·openSUSE
  • cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:* Versions 15.2 Vulnerable ·openSUSE

Remediation

  • Fix · CNA puma (puma) Fixed in 3.12.6, 4.3.5
  • Fix · GHSA-w64w-qqph-5gxm puma (RubyGems) Fixed in 3.12.6 Advisory →
  • Fix · GHSA-w64w-qqph-5gxm puma (RubyGems) Fixed in 4.3.5 Advisory →

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    puma — openSUSE-SU-2020:0990

    2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2020-08950 HTTP Smuggling via Transfer-Encoding Header in PumaPriority MEDIUM 40
    Show all 2 records → Advisory →
  • Advisory ·

    puma — openSUSE-SU-2020:1001

    2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2020-08950 HTTP Smuggling via Transfer-Encoding Header in PumaPriority MEDIUM 40
    Show all 2 records → Advisory →
Show 1 more group
  • Advisory ·

    puma — FEDORA-2020-fe354f24e8

    2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2020-08950 HTTP Smuggling via Transfer-Encoding Header in PumaPriority MEDIUM 40
    Show all 2 records → Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
CloudForms Management Engine 5AffectedNo fix planned: Will not fix
Red Hat Storage 3AffectedNo fix planned: Will not fix

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-11077
  2. 2026-10-03 Alias added: GHSA-w64w-qqph-5gxm

References

Advisory 6

Other 4

  • TI-2022-08603 HTTP Request Smuggling in puma CVSS 3.1CRITICAL 9.1
  • TI-2023-21048 Inconsistent Interpretation of HTTP Requests in puma CVSS 3.1CRITICAL 9.8
  • TI-2022-07686 Information Exposure when using Puma with Rails CVSS 3.1HIGH 8.0
  • TI-2020-08950 HTTP Smuggling via Transfer-Encoding Header in Puma CVSS 3.1HIGH 7.5
  • TI-2020-04303 HTTP Response Splitting in Puma CVSS 3.1HIGH 7.5
  • TI-2019-12551 Potential DOS attack in Puma CVSS 3.1HIGH 7.5
See all 11 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences