CVE-2020-11077
mediumpriority · track · 31EPSS 0.029 · 87 %ileEUUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (10)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- GHSA-w64w-qqph-5gxmHTTP Smuggling via Transfer-Encoding Header in Puma2020-05-22ghsa · osvUS
### Impact This is a similar but different vulnerability to the one patched in 3.12.5 and 4.3.4. 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. ### Patches The problem has been fixed in Puma 3.12.6 and Puma 4.3.5. ### For more information If you have any questions or comments about this advisory: * Open an issue in [Puma](https://github.com/puma/puma) * See our [security policy](https://github.com/puma/puma/security/policy)
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (25)
External citations — patches, advisories, analysis.
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00034.htmlcnnvd
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00038.htmlcnnvd
- https://github.com/puma/puma/blob/master/History.md#434435-and-31253126--2020-05-22cnnvd
- https://github.com/puma/puma/security/advisories/GHSA-w64w-qqph-5gxmcnnvd
- https://lists.debian.org/debian-lts-announce/2020/10/msg00009.htmlcnnvd
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SKIY5H67GJIGJL6SMFWFLUQQQR3EMVPR/cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2020-11077cnnvd
- https://vigilance.fr/vulnerability/RubyGem-Puma-read-write-access-via-HTTP-Pipelining-32877cnnvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan