Http4s Ember HTTP/2: unbounded outbound frame queue
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 0.23.35, 1.0.0-M47
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember HTTP/2 serializes outbound frames through one unbounded queue consumed by writeLoop. When the peer stops reading, an unauthenticated HTTP/2 client can continue sending PING, SETTINGS, or DATA frames that cause Ember to enqueue acknowledgments or WINDOW_UPDATE frames faster than the writer drains them, exhausting heap memory on a server built with withHttp2. The shared behavior also affects an ember-client connected to a hostile HTTP/2 server, and the patch replaces the unbounded path with bounded, backpressured outbound queues. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- http4s http4s
fixed in 0.23.35; From 1.0.0-M1 · fixed in 1.0.0-M47
- org.http4s:http4s-ember-core_2.12Maven
fixed in 0.23.35
- org.http4s:http4s-ember-core_2.13Maven
fixed in 0.23.35
- org.http4s:http4s-ember-core_3Maven
fixed in 0.23.35
- org.http4s:http4s-ember-core_3Maven
From 1.0.0-M1 · fixed in 1.0.0-M47
- org.http4s:http4s-ember-core_2.13Maven
From 1.0.0-M1 · fixed in 1.0.0-M47