CVE-2020-11077
MEDIUMEPSS 85th pctlDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
Exploit Intelligence
Elevated risk: more likely to be exploited than 85% of all known CVEs.
References
Related Vulnerabilities
Other CWE-444 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-22536 | Critical | 10.0 | 98% | KEV | - |
| CVE-2025-61884 | High | 7.5 | 98% | KEV + Ransom | - |
| CVE-2020-9490 | High | 7.5 | 90% | - | Fix |
| CVE-2023-41265 | Critical | 9.6 | 84% | KEV + Ransom | - |
| CVE-2023-25690 | Critical | 9.8 | 84% | - | Fix |
| CVE-2022-32214 | Medium | 6.5 | 81% | - | Fix |
Common questions
How do I fix CVE-2020-11077?
Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2020-11077 being actively exploited?
Not that we know of. CVE-2020-11077 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 2.8% is the estimated probability that it will be exploited in the next 30 days. That is higher than 85% of all scored CVEs.
How severe is CVE-2020-11077?
CVE-2020-11077 has a CVSS v3 base score of 6.8, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2020-11077 affect?
Published advisories record a fix for puma (Debian), puma (Ubuntu). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.