CVE-2020-5249
HTTP Response Splitting (Early Hints) in Puma
Description
In Puma (RubyGem) before 4.3.3 and 3.12.4, if an application using Puma allows untrusted input in an early-hints header, an attacker can use a carriage return character to end the header and inject malicious content, such as additional headers or an entirely new response body. This vulnerability is known as HTTP Response Splitting. While not an attack in itself, response splitting is a vector for several other attacks, such as cross-site scripting (XSS). This is related to CVE-2020-5247, which fixed this vulnerability but only for regular responses. This has been fixed in 4.3.3 and 3.12.4.
How to fix CVE-2020-5249
To remediate CVE-2020-5249, upgrade the affected package to a fixed version below.
- —upgrade to 3.12.4-1 or later
- —upgrade to 3.12.4 or later
Is CVE-2020-5249 being exploited?
Low — EPSS is 0.5%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 3.12.4-1
- from 0, < 3.12.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L |