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GHSA-w64w-qqph-5gxm

MediumCVSS 6.8 / 10
Published May 22, 2020·Last modified Mar 13, 2026
Affected Components(0)

No affected components available

Description

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:

Risk Scores
Base Score
6.8

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the integrity of the data.

Threat Intelligence
6.2

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
2.81%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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