{"items":[{"id":"NVI-00015368","kind":"vulnerability","title":"Http4s Ember HTTP/2 does not enforce SETTINGS_MAX_CONCURRENT_STREAMS","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-9vwc-pc8p-253q","CVE-2026-69203"],"plain_summary":"GitHub lists this reviewed advisory for org.http4s:http4s-ember-core_2.12, org.http4s:http4s-ember-core_2.13, org.http4s:http4s-ember-core_3, org.http4s:http4s-ember-core_2.13, org.http4s:http4s-ember-core_3. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-60b64aaa2b8f87272ea0a7fce9201b75"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-09-15T19:53:27.000Z","value":"7.5 high","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-60b64aaa2b8f87272ea0a7fce9201b75"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-60b64aaa2b8f87272ea0a7fce9201b75","url":"https://github.com/advisories/GHSA-9vwc-pc8p-253q","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-9vwc-pc8p-253q","publisher":"GitHub Advisory Database","observed_at":"2026-11-01T19:09:30.244Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-60b64aaa2b8f87272ea0a7fce9201b75"],"technology":"org.http4s:http4s-ember-core_2.12","known_exclusions":[],"conditions_summary":"An ember server with HTTP/2 enabled (`.withHttp2`) does not enforce `SETTINGS_MAX_CONCURRENT_STREAMS` on streams opened by the peer.  A single unauthenticated connection can open an unbounded number of concurrent streams, each of which allocates per-stream server state that is never released, exhausting the heap.\n\n## Impact\n\nUnauthenticated remote denial of service (memory exhaustion) against any Ember server built `.withHttp2`.  This is the resource-exhaustion class of the HTTP/2 \"Rapid Reset\" family (CVE-2023-44487).\n\nThe same unchecked allocation path is reachable on the client via server-initiated `PUSH_PROMISE` frames, so a malicious or compromised server can exhaust an ember-client's heap the same way.\n\n## Preconditions\n\n- Server: with `.withHttp2` enabled.\n- Client: makes HTTP/2 requests to malicious or compromised sites.  `enablePush` is not enforced.\n\n## Workarounds\n\n- Disable HTTP/2 on `EmberServerBuilder` or `EmberClientBuilder` (default)\n- Client only: avoid HTTP/2 to untrusted servers until patched.","public_affected_ranges":["<= 0.23.34"]},{"certainty":"source_listed","source_ids":["sr-60b64aaa2b8f87272ea0a7fce9201b75"],"technology":"org.http4s:http4s-ember-core_2.13","known_exclusions":[],"conditions_summary":"An ember server with HTTP/2 enabled (`.withHttp2`) does not enforce `SETTINGS_MAX_CONCURRENT_STREAMS` on streams opened by the peer.  A single unauthenticated connection can open an unbounded number of concurrent streams, each of which allocates per-stream server state that is never released, exhausting the heap.\n\n## Impact\n\nUnauthenticated remote denial of service (memory exhaustion) against any Ember server built `.withHttp2`.  This is the resource-exhaustion class of the HTTP/2 \"Rapid Reset\" family (CVE-2023-44487).\n\nThe same unchecked allocation path is reachable on the client via server-initiated `PUSH_PROMISE` frames, so a malicious or compromised server can exhaust an ember-client's heap the same way.\n\n## Preconditions\n\n- Server: with `.withHttp2` enabled.\n- Client: makes HTTP/2 requests to malicious or compromised sites.  `enablePush` is not enforced.\n\n## Workarounds\n\n- Disable HTTP/2 on `EmberServerBuilder` or `EmberClientBuilder` (default)\n- Client only: avoid HTTP/2 to untrusted servers until patched.","public_affected_ranges":["<= 0.23.34"]},{"certainty":"source_listed","source_ids":["sr-60b64aaa2b8f87272ea0a7fce9201b75"],"technology":"org.http4s:http4s-ember-core_3","known_exclusions":[],"conditions_summary":"An ember server with HTTP/2 enabled (`.withHttp2`) does not enforce `SETTINGS_MAX_CONCURRENT_STREAMS` on streams opened by the peer.  A single unauthenticated connection can open an unbounded number of concurrent streams, each of which allocates per-stream server state that is never released, exhausting the heap.\n\n## Impact\n\nUnauthenticated remote denial of service (memory exhaustion) against any Ember server built `.withHttp2`.  This is the resource-exhaustion class of the HTTP/2 \"Rapid Reset\" family (CVE-2023-44487).\n\nThe same unchecked allocation path is reachable on the client via server-initiated `PUSH_PROMISE` frames, so a malicious or compromised server can exhaust an ember-client's heap the same way.\n\n## Preconditions\n\n- Server: with `.withHttp2` enabled.\n- Client: makes HTTP/2 requests to malicious or compromised sites.  `enablePush` is not enforced.\n\n## Workarounds\n\n- Disable HTTP/2 on `EmberServerBuilder` or `EmberClientBuilder` (default)\n- Client only: avoid HTTP/2 to untrusted servers until patched.","public_affected_ranges":["<= 0.23.34"]},{"certainty":"source_listed","source_ids":["sr-60b64aaa2b8f87272ea0a7fce9201b75"],"technology":"org.http4s:http4s-ember-core_2.13","known_exclusions":[],"conditions_summary":"An ember server with HTTP/2 enabled (`.withHttp2`) does not enforce `SETTINGS_MAX_CONCURRENT_STREAMS` on streams opened by the peer.  A single unauthenticated connection can open an unbounded number of concurrent streams, each of which allocates per-stream server state that is never released, exhausting the heap.\n\n## Impact\n\nUnauthenticated remote denial of service (memory exhaustion) against any Ember server built `.withHttp2`.  This is the resource-exhaustion class of the HTTP/2 \"Rapid Reset\" family (CVE-2023-44487).\n\nThe same unchecked allocation path is reachable on the client via server-initiated `PUSH_PROMISE` frames, so a malicious or compromised server can exhaust an ember-client's heap the same way.\n\n## Preconditions\n\n- Server: with `.withHttp2` enabled.\n- Client: makes HTTP/2 requests to malicious or compromised sites.  `enablePush` is not enforced.\n\n## Workarounds\n\n- Disable HTTP/2 on `EmberServerBuilder` or `EmberClientBuilder` (default)\n- Client only: avoid HTTP/2 to untrusted servers until patched.","public_affected_ranges":[">= 1.0.0-M1, <= 1.0.0-M46"]},{"certainty":"source_listed","source_ids":["sr-60b64aaa2b8f87272ea0a7fce9201b75"],"technology":"org.http4s:http4s-ember-core_3","known_exclusions":[],"conditions_summary":"An ember server with HTTP/2 enabled (`.withHttp2`) does not enforce `SETTINGS_MAX_CONCURRENT_STREAMS` on streams opened by the peer.  A single unauthenticated connection can open an unbounded number of concurrent streams, each of which allocates per-stream server state that is never released, exhausting the heap.\n\n## Impact\n\nUnauthenticated remote denial of service (memory exhaustion) against any Ember server built `.withHttp2`.  This is the resource-exhaustion class of the HTTP/2 \"Rapid Reset\" family (CVE-2023-44487).\n\nThe same unchecked allocation path is reachable on the client via server-initiated `PUSH_PROMISE` frames, so a malicious or compromised server can exhaust an ember-client's heap the same way.\n\n## Preconditions\n\n- Server: with `.withHttp2` enabled.\n- Client: makes HTTP/2 requests to malicious or compromised sites.  `enablePush` is not enforced.\n\n## Workarounds\n\n- Disable HTTP/2 on `EmberServerBuilder` or `EmberClientBuilder` (default)\n- Client only: avoid HTTP/2 to untrusted servers until patched.","public_affected_ranges":[">= 1.0.0-M1, <= 1.0.0-M46"]}],"null_published_at":"2026-11-03T10:03:31.358Z","source_updated_at":"2026-09-15T19:53:27.000Z","source_disclosed_at":"2026-09-15T19:53:14.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-01T19:09:30.244Z"}],"next_cursor":null,"snapshot_revision":"42594"}