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CVE-2020-11076HTTP Smuggling via Transfer-Encoding Header in Puma
- 7.5HighCVSS base score
- 4.1%Exploitation in 30 daysEPSS · top 9.1% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In Puma (RubyGem) before 4.3.4 and 3.12.5, an attacker could smuggle an HTTP response, by using an invalid transfer-encoding header. The problem has been fixed in Puma 3.12.5 and Puma 4.3.4.
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 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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)
- 4.1% · top 9.1% of all CVEs (12 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- RubyGemspumaGHSA-x7jg-6pwg-fx5h (opens in a new tab)
References
References7
- https://github.com/puma/puma/security/advisories/GHSA-x7jg-6pwg-fx5h (opens in a new tab)x_refsource_CONFIRMx_transferred
- 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/commit/f24d5521295a2152c286abb0a45a1e1e2bd275bd (opens in a new tab)x_refsource_MISCx_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-2020-0447 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-x7jg-6pwg-fx5h (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-2020-11076)Record last updated .