{"id":"CVE-2026-88975","title":"Http4s is a Scala interface for HTTP services","summary":"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 u…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-400"],"vendor":"http4s","product":"http4s","affected":["http4s < 0.23.37","http4s >= 1.0.0-M1, < 1.0.0-M48"],"patched":["org.http4s:http4s-ember-core_2.13 0.23.37","org.http4s:http4s-ember-core_2.12 0.23.37","org.http4s:http4s-ember-core_3 0.23.37","org.http4s:http4s-ember-core_2.13 1.0.0-M48","org.http4s:http4s-ember-core_3 1.0.0-M48"],"published":"2026-09-15","updated":"2026-09-16","sourceUpdated":"2026-09-16T20:39:16.610","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-88975","references":[{"url":"https://github.com/http4s/http4s/commit/87cf334fa3f608ef7d3eb359e71e037ba3336d29","label":"security-advisories@github.com"},{"url":"https://github.com/http4s/http4s/releases/tag/v0.23.37","label":"security-advisories@github.com"},{"url":"https://github.com/http4s/http4s/releases/tag/v1.0.0-M48","label":"security-advisories@github.com"},{"url":"https://github.com/http4s/http4s/security/advisories/GHSA-gq9p-f254-h286","label":"security-advisories@github.com"},{"url":"https://github.com/advisories/GHSA-gq9p-f254-h286"}],"tags":["nvd","cve.org","ghsa","maven"],"aliases":["GHSA-gq9p-f254-h286"],"ecosystem":"maven","ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-09-16T14:43:06.919100Z"},"ingestedAt":"2026-09-15T19:42:58.816Z","epss":0.00622,"epssPercentile":0.48133,"slug":"CVE-2026-88975","body":"## Overview\n\nHttp4s 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-88975)\n\nAffected packages:\n\n- `org.http4s:http4s-ember-core_2.13 <= 0.23.36`\n- `org.http4s:http4s-ember-core_2.12 <= 0.23.36`\n- `org.http4s:http4s-ember-core_3 <= 0.23.36`\n- `org.http4s:http4s-ember-core_2.13 >= 1.0.0-M1, <= 1.0.0-M47`\n- `org.http4s:http4s-ember-core_3 >= 1.0.0-M1, <= 1.0.0-M47`\n\nPatched in:\n\n- `org.http4s:http4s-ember-core_2.13 0.23.37`\n- `org.http4s:http4s-ember-core_2.12 0.23.37`\n- `org.http4s:http4s-ember-core_3 0.23.37`\n- `org.http4s:http4s-ember-core_2.13 1.0.0-M48`\n- `org.http4s:http4s-ember-core_3 1.0.0-M48`\n\nSource: https://github.com/advisories/GHSA-gq9p-f254-h286","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}