CVE-2026-69202High· 7.5▾ TwilightHttp4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HTTP/2 flow-control window is replenished according to bytes received from the network rather than bytes consumed by the application, while each strea…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.1 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Sep 19.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Last analysed / modified upstream
0.4%
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HTTP/2 flow-control window is replenished according to bytes received from the network rather than bytes consumed by the application, while each stream stores DATA in an unbounded channel. A hostile peer can therefore send a body faster than a slow or non-draining application consumes it, retaining payloads in heap on an ember-server or ember-client configured with withHttp2. The patch bounds the per-stream H2Connection body channel so application consumption applies backpressure. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
org.http4s:http4s-ember-core_2.12 <= 0.23.34org.http4s:http4s-ember-core_2.13 <= 0.23.34org.http4s:http4s-ember-core_3 <= 0.23.34org.http4s:http4s-ember-core_2.13 >= 1.0.0-M1, <= 1.0.0-M46org.http4s:http4s-ember-core_3 >= 1.0.0-M1, <= 1.0.0-M46Patched in:
org.http4s:http4s-ember-core_2.12 0.23.35org.http4s:http4s-ember-core_2.13 0.23.35org.http4s:http4s-ember-core_3 0.23.35org.http4s:http4s-ember-core_2.13 1.0.0-M47org.http4s:http4s-ember-core_3 1.0.0-M47Connected by shared product, vendor, weakness, or advisory.
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