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CVE-2020-11077

20
FAUCET Score

CVE-2020-11077 is a request smuggling vulnerability affecting Puma (RubyGem) versions prior to 4.3.5 and 3.12.6, as well as various Debian, Fedora, and openSUSE distributions. An attacker could manipulate HTTP pipelining to cause a proxy to misdirect a response intended for one client to another, potentially exposing sensitive information or enabling further attacks. With a CVSS score of 7.5 (High), this vulnerability has a network attack vector and low attack complexity, but its impact is limited to integrity. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 3.0.0, < 3.12.6CPE matchmatch criteria
cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:*
>= 4.0.0, < 4.3.5CPE matchmatch criteria
cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
15.1CPE matchmatch criteria
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.8MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
4.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.81%
Probability of exploitation in next 30 days
EPSS Percentile
85.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0281 is in the 73rd percentile among its peer group of 51,485 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (5)

rubygemspatch availablevia ghsa
Product: pumaFixed in: 3.12.6
rubygemspatch availablevia ghsa
Product: pumaFixed in: 4.3.5
github_advisoryvendor investigatingvia nvd_reference
View patch
redhatend of lifevia redhat_api
Product: CloudForms Management Engine 5Fixed in: rubygem-puma
redhatend of lifevia redhat_api
Product: Red Hat Storage 3Fixed in: rubygem-puma

Vendor Advisories (2)

rubygemsGHSA-w64w-qqph-5gxmmedium

HTTP Smuggling via Transfer-Encoding Header in Puma

May 22, 2020
redhatCVE-2020-11077Moderate

rubygem-puma: HTTP Smuggling through a proxy via Transfer-Encoding Header

May 21, 2020

References

lists.opensuse.org / opensuse-security-announce/2020-07/msg00034.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-07/msg00038.html
Mailing ListThird Party Advisory
github.com / puma/puma/blob/master/History.md
Release Notes
github.com / puma/puma/security/advisories/GHSA-w64w-qqph-5gxm
Vendor Advisory
lists.debian.org / debian-lts-announce/2020/10/msg00009.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/SKIY5H67GJIGJL6SMFWFLUQQQR3EMVPR