CVE-2020-11077HTTP Smuggling via Transfer-Encoding Header in Puma
- 6.8MediumCVSS base score
- 2.9%Exploitation in 30 daysEPSS · top 13% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By GitHub_M
- 53 days later
· 53 days later
Published
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium6.8 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 2.9% · top 13% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.8.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- RubyGemspumaGHSA-w64w-qqph-5gxm (opens in a new tab)
References
References6
- https://github.com/puma/puma/blob/master/History.md#434435-and-31253126--2020-05-22 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/puma/puma/security/advisories/GHSA-w64w-qqph-5gxm (opens in a new tab)x_refsource_CONFIRMx_transferred
- openSUSE-SU-2020:0990 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- openSUSE-SU-2020:1001 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- FEDORA-2020-fe354f24e8 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- [debian-lts-announce] 20201007 [SECURITY] [DLA 2398-1] puma security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2020-0445 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-w64w-qqph-5gxm (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2020-11077)Record last updated .