CVE-2019-16770
Potential DOS attack in Puma
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
In Puma before versions 3.12.2 and 4.3.1, a poorly-behaved client could use keepalive requests to monopolize Puma's reactor and create a denial of service attack. If more keepalive connections to Puma are opened than there are threads available, additional connections will wait permanently if the attacker sends requests frequently enough. This vulnerability is patched in Puma 4.3.1 and 3.12.2.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 2.0% · top 19% of all CVEs (6 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- RubyGemspumaGHSA-7xx3-m584-x994 (opens in a new tab)
What to do
Workaround: Reverse proxies in front of Puma could be configured to always allow less than X keepalive connections to a Puma cluster or process, where X is the number of threads configured in Puma's thread pool.
References (2)
- https://github.com/puma/puma/security/advisories/GHSA-7xx3-m584-x994 (opens in a new tab)x_refsource_CONFIRMx_transferred
- [debian-lts-announce] 20220525 [SECURITY] [DLA 3023-1] 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)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-7xx3-m584-x994 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2019-16770)Record last updated .