CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVE-2026-88975
High (7.5). EPSS 0.6% chance of exploitation in the next 30 days. Fixed in org.http4s:http4s-ember-core_2.13 0.23.37, 1.0.0-M48.
Http4s is a Scala interface for HTTP services. Prior to 0.23.37 and 1.0.0-M48, Ember’s HTTP/2 read loop parses a frame’s 24-bit declared length but waits to buffer the entire payload before comparing it with SETTINGS_MAX_FRAME_SIZE. An unauthenticated peer can declare a payload near 16 MiB on a connection where Ember advertised 16 KiB and either complete or slowly stream it, causing up to 1024-fold memory amplification per connection before processFrame can reject the frame. The shared H2Connection.readLoop affects withHttp2 servers and clients, while HTTP/2-disabled configurations are unaffected, and the patch rejects oversized frames before buffering their payloads. This issue is fixed in versions 0.23.37 and 1.0.0-M48.
Severity
- EPSS
- 0.6% chance of exploitation in the next 30 days; higher than 50% of CVEs (scores of 2026-10-31)
- CWE
- CWE-400
- Published
- Modified
- Record from
- the NVD, synced
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-gq9p-f254-h286 | Maven | org.http4s:http4s-ember-core_2.13 | <0.23.37 | 0.23.37 |
| GHSA-gq9p-f254-h286 | Maven | org.http4s:http4s-ember-core_2.12 | <0.23.37 | 0.23.37 |
| GHSA-gq9p-f254-h286 | Maven | org.http4s:http4s-ember-core_3 | <0.23.37 | 0.23.37 |
| GHSA-gq9p-f254-h286 | Maven | org.http4s:http4s-ember-core_2.13 | >=1.0.0-M1 <1.0.0-M48 | 1.0.0-M48 |
| GHSA-gq9p-f254-h286 | Maven | org.http4s:http4s-ember-core_3 | >=1.0.0-M1 <1.0.0-M48 | 1.0.0-M48 |