CVE-2026-69209

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The shared WebSocket decoder permits unbounded message buffering because defragmentation accumulates fragments without a limit and FrameTranscoder accepts declared lengths up to Int.MaxValue. A remote client that completes a WebSocket handshake against an http4s-blaze-server or http4s-ember-server endpoint can exhaust server memory with oversized frames or fragmented messages. The patched decoder applies a configurable 64 MiB default limit to individual frames and defragmented messages through EmberServerBuilder.withMaxWebSocketMessageSize. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/http4s/http4s/commit/d578c3c9da6193627d40fa785e612cda7fcd77b3
https://github.com/http4s/http4s/releases/tag/v0.23.35
https://github.com/http4s/http4s/releases/tag/v1.0.0-M47
https://github.com/http4s/http4s/security/advisories/GHSA-jrxx-w2m8-5hf5

Configurations

No configuration.

History

No history.

Information

Published : 2026-09-15 19:17

Updated : 2026-09-15 19:17

NVD link : CVE-2026-69209

Mitre link : CVE-2026-69209

CVE.ORG link : CVE-2026-69209

JSON object : View

Products Affected

No product.

CWE

CWE-400

Uncontrolled Resource Consumption

CWE-770

Allocation of Resources Without Limits or Throttling

{"id": "CVE-2026-69209", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "http4s", "product": "http4s", "versions": [{"status": "affected", "version": "< 0.23.35"}, {"status": "affected", "version": ">= 1.0.0-M1, < 1.0.0-M47"}]}]}], "published": "2026-09-15T19:17:37.870", "references": [{"url": "https://github.com/http4s/http4s/commit/d578c3c9da6193627d40fa785e612cda7fcd77b3", "source": "security-advisories@github.com"}, {"url": "https://github.com/http4s/http4s/releases/tag/v0.23.35", "source": "security-advisories@github.com"}, {"url": "https://github.com/http4s/http4s/releases/tag/v1.0.0-M47", "source": "security-advisories@github.com"}, {"url": "https://github.com/http4s/http4s/security/advisories/GHSA-jrxx-w2m8-5hf5", "source": "security-advisories@github.com"}], "vulnStatus": "Received", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-770"}]}], "descriptions": [{"lang": "en", "value": "Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The shared WebSocket decoder permits unbounded message buffering because defragmentation accumulates fragments without a limit and FrameTranscoder accepts declared lengths up to Int.MaxValue. A remote client that completes a WebSocket handshake against an http4s-blaze-server or http4s-ember-server endpoint can exhaust server memory with oversized frames or fragmented messages. The patched decoder applies a configurable 64 MiB default limit to individual frames and defragmented messages through EmberServerBuilder.withMaxWebSocketMessageSize. This issue is fixed in versions 0.23.35 and 1.0.0-M47."}], "lastModified": "2026-09-15T19:17:37.870", "sourceIdentifier": "security-advisories@github.com"}