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.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-400",
"CWE-770"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/69xxx/CVE-2026-69213.json"
}{
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "0.23.35"
},
{
"introduced": "1.0.0-M1"
},
{
"fixed": "1.0.0-M47"
}
],
"source": [
"AFFECTED_FIELD",
"REFERENCES"
]
}