What is the CVSS score of CVE-2021-41136?

CVE-2021-41136 has a CVSS 3.1 base score of 3.7 (Low). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N. EPSS exploitation probability: 1.1%.

Is there a patch available for CVE-2021-41136?

Yes, a patch is available for CVE-2021-41136. Update the affected software to the latest version immediately.

Puma CVE-2021-41136

LOW

HTTP Request/Response Smuggling (CWE-444)

2021-10-12 security-advisories@github.com

Request Smuggling Apache Information Disclosure Puma Debian Linux

3.7

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

3.7 LOW

AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

Low

User Interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

CVE Published

Oct 12, 2021 - 16:15 nvd

LOW 3.7

DescriptionNVD

Puma is a HTTP 1.1 server for Ruby/Rack applications. Prior to versions 5.5.1 and 4.3.9, using puma with a proxy which forwards HTTP header values which contain the LF character could allow HTTP request smugggling. A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client. The only proxy which has this behavior, as far as the Puma team is aware of, is Apache Traffic Server. 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 vulnerability was patched in Puma 5.5.1 and 4.3.9. As a workaround, do not use Apache Traffic Server with puma.

AnalysisAI

Puma is a HTTP 1.1 server for Ruby/Rack applications. Rated low severity (CVSS 3.7), this vulnerability is remotely exploitable. This HTTP Request/Response Smuggling vulnerability could allow attackers to manipulate HTTP request interpretation between frontend and backend servers.

Technical ContextAI

This vulnerability is classified as HTTP Request/Response Smuggling (CWE-444), which allows attackers to manipulate HTTP request interpretation between frontend and backend servers. Puma is a HTTP 1.1 server for Ruby/Rack applications. Prior to versions 5.5.1 and 4.3.9, using puma with a proxy which forwards HTTP header values which contain the LF character could allow HTTP request smugggling. A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client. The only proxy which has this behavior, as far as the Puma team is aware of, is Apache Traffic Server. 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 vulnerability was patched in Puma 5.5.1 and 4.3.9. As a workaround, do not use Apache Traffic Server with puma. Affected products include: Puma, Debian Debian Linux.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Enforce strict HTTP parsing, normalize requests at proxy layer, use HTTP/2 end-to-end, reject ambiguous headers.