CVE-2021-41136
CVE-2021-41136 — Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') in puma
Puma is a HTTP 1.1 server for Ruby/Rack applications. Prior to versions 5.5.1 and 4.3.9, using `puma` with a proxy which forwards HTTP header values which contain the LF character could allow HTTP request smugggling. A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client. The only proxy which has this behavior, as far as the Puma team is aware of, is Apache Traffic Server. 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…
Published Updated Sources: cvelistV5, GitHub_M
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
1%
chance of exploitation in 30 days
CVSS base
3.7
LOW
Affected scope
The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.
Vendors (1)
Products (1)
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 3.7 | CVSS 3.1 | LOW | — | — | cvelistV5 |
Weakness & attack patterns
- CWE-444
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Search application, proxy, and WAF logs for requests touching /Rack.
References
7 on the record
- github.com/puma/puma/security/advisories/GHSA-48w2-rm65-62xx
x_refsource_CONFIRM
- github.com/puma/puma/commit/436c71807f00e07070902a03f79fd3e130eb6b18
x_refsource_MISC
- github.com/puma/puma/commit/acdc3ae571dfae0e045cf09a295280127db65c7f
x_refsource_MISC
- github.com/puma/puma/commit/fb6ad8f8013ab5cdbb2f444cbfabd0b4fde71139
x_refsource_MISC
- www.debian.org/security/2022/dsa-5146
vendor-advisory, x_refsource_DEBIAN, x_transferred
- security.gentoo.org/glsa/202208-28
vendor-advisory, x_refsource_GENTOO, x_transferred
- lists.debian.org/debian-lts-announce/2022/08/msg00015.html
mailing-list, x_refsource_MLIST, x_transferred
Elsewhere on this site
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.