CVE-2019-16770
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (2.01%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 2.01% probability · 81th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-770
- Affected
- puma/puma · debian/debian linux
- Source
- security-advisories@github.com
EPSS 2.0% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/puma/puma/security/advisories/GHSA-7xx3-m584-x994Mitigation, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/05/msg00034.htmlMailing List, Third Party Advisory
- https://github.com/puma/puma/security/advisories/GHSA-7xx3-m584-x994Mitigation, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/05/msg00034.htmlMailing List, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.