CVE-2021-41136

NameCVE-2021-41136
DescriptionPuma 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 second client. This vulnerability was patched in Puma 5.5.1 and 4.3.9. As a workaround, do not use Apache Traffic Server with `puma`.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3083-1, DSA-5146-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
puma (PTS)stretch (security), stretch (lts), stretch3.6.0-1+deb9u2vulnerable
buster3.12.0-2+deb10u2vulnerable
buster (security)3.12.0-2+deb10u3fixed
bullseye4.3.8-1vulnerable
bullseye (security)4.3.8-1+deb11u2fixed
bookworm5.6.5-3fixed
sid, trixie6.4.2-4fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
pumasourcebuster3.12.0-2+deb10u3DLA-3083-1
pumasourcebullseye4.3.8-1+deb11u2DSA-5146-1
pumasource(unstable)5.5.2-1

Notes

[stretch] - puma <no-dsa> (Minor issue)
https://github.com/puma/puma/security/advisories/GHSA-48w2-rm65-62xx
https://github.com/puma/puma/commit/acdc3ae571dfae0e045cf09a295280127db65c7f

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