Vulnerability-Lookup

CVE-2026-69210 (GCVE-0-2026-69210)

Vulnerability from cvelistv5 – Published: 2026-09-15 19:19 – Updated: 2026-09-15 19:19

Title

Http4s: WebSocket decoder accepts negative length, causing infinite decode loop

Summary

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, WebSocket FrameTranscoder.bodyLength rejects extended payload lengths above Integer.MAX_VALUE but permits negative 64-bit lengths. A remote client that completes a WebSocket handshake through an Ember server can send such a frame, causing the decoder to return an empty frame without advancing its input. The decode loop then runs indefinitely, pins a worker at full CPU, and grows an ArrayBuffer without bound, resulting in denial of service. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE

CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')
CWE-1284 - Improper Validation of Specified Quantity in Input

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/http4s/http4s/security/advisor…	x_refsource_CONFIRM
https://github.com/http4s/http4s/commit/c7d3ef90d…	x_refsource_MISC
https://github.com/http4s/http4s/releases/tag/v0.23.35	x_refsource_MISC
https://github.com/http4s/http4s/releases/tag/v1.…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
http4s	http4s	Affected: < 0.23.35 Affected: >= 1.0.0-M1, < 1.0.0-M47	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "http4s",
          "vendor": "http4s",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.23.35"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.0.0-M1, \u003c 1.0.0-M47"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, WebSocket FrameTranscoder.bodyLength rejects extended payload lengths above Integer.MAX_VALUE but permits negative 64-bit lengths. A remote client that completes a WebSocket handshake through an Ember server can send such a frame, causing the decoder to return an empty frame without advancing its input. The decode loop then runs indefinitely, pins a worker at full CPU, and grows an ArrayBuffer without bound, resulting in denial of service. This issue is fixed in versions 0.23.35 and 1.0.0-M47."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-835",
              "description": "CWE-835: Loop with Unreachable Exit Condition (\u0027Infinite Loop\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-1284",
              "description": "CWE-1284: Improper Validation of Specified Quantity in Input",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-15T19:19:04.868Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/http4s/http4s/security/advisories/GHSA-3j86-pj9g-jchr",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/http4s/http4s/security/advisories/GHSA-3j86-pj9g-jchr"
        },
        {
          "name": "https://github.com/http4s/http4s/commit/c7d3ef90dc2ed1cd464968ab1b34f2f1762ddae2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/http4s/commit/c7d3ef90dc2ed1cd464968ab1b34f2f1762ddae2"
        },
        {
          "name": "https://github.com/http4s/http4s/releases/tag/v0.23.35",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/http4s/releases/tag/v0.23.35"
        },
        {
          "name": "https://github.com/http4s/http4s/releases/tag/v1.0.0-M47",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/http4s/releases/tag/v1.0.0-M47"
        }
      ],
      "source": {
        "advisory": "GHSA-3j86-pj9g-jchr",
        "discovery": "UNKNOWN"
      },
      "title": "Http4s: WebSocket decoder accepts negative length, causing infinite decode loop"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-69210",
    "datePublished": "2026-09-15T19:19:04.868Z",
    "dateReserved": "2026-08-03T16:57:50.124Z",
    "dateUpdated": "2026-09-15T19:19:04.868Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-69210",
      "date": "2026-09-16",
      "epss": "0.00466",
      "percentile": "0.39301"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-69210\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-09-15T20:17:40.320\",\"lastModified\":\"2026-09-16T20:38:04.943\",\"vulnStatus\":\"Deferred\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, WebSocket FrameTranscoder.bodyLength rejects extended payload lengths above Integer.MAX_VALUE but permits negative 64-bit lengths. A remote client that completes a WebSocket handshake through an Ember server can send such a frame, causing the decoder to return an empty frame without advancing its input. The decode loop then runs indefinitely, pins a worker at full CPU, and grows an ArrayBuffer without bound, resulting in denial of service. This issue is fixed in versions 0.23.35 and 1.0.0-M47.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"http4s\",\"product\":\"http4s\",\"versions\":[{\"version\":\"\u003c 0.23.35\",\"status\":\"affected\"},{\"version\":\"\u003e= 1.0.0-M1, \u003c 1.0.0-M47\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-835\"},{\"lang\":\"en\",\"value\":\"CWE-1284\"}]}],\"references\":[{\"url\":\"https://github.com/http4s/http4s/commit/c7d3ef90dc2ed1cd464968ab1b34f2f1762ddae2\",\"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-3j86-pj9g-jchr\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}

FKIE_CVE-2026-69210

Vulnerability from fkie_nvd - Published: 2026-09-15 20:17 - Updated: 2026-09-16 20:38

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/http4s/http4s/commit/c7d3ef90dc2ed1cd464968ab1b34f2f1762ddae2
	security-advisories@github.com	https://github.com/http4s/http4s/releases/tag/v0.23.35
	security-advisories@github.com	https://github.com/http4s/http4s/releases/tag/v1.0.0-M47
	security-advisories@github.com	https://github.com/http4s/http4s/security/advisories/GHSA-3j86-pj9g-jchr

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "http4s",
          "vendor": "http4s",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.23.35"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.0.0-M1, \u003c 1.0.0-M47"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, WebSocket FrameTranscoder.bodyLength rejects extended payload lengths above Integer.MAX_VALUE but permits negative 64-bit lengths. A remote client that completes a WebSocket handshake through an Ember server can send such a frame, causing the decoder to return an empty frame without advancing its input. The decode loop then runs indefinitely, pins a worker at full CPU, and grows an ArrayBuffer without bound, resulting in denial of service. This issue is fixed in versions 0.23.35 and 1.0.0-M47."
    }
  ],
  "id": "CVE-2026-69210",
  "lastModified": "2026-09-16T20:38:04.943",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-15T20:17:40.320",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/http4s/commit/c7d3ef90dc2ed1cd464968ab1b34f2f1762ddae2"
    },
    {
      "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-3j86-pj9g-jchr"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-835"
        },
        {
          "lang": "en",
          "value": "CWE-1284"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.