Vulnerability-Lookup

CVE-2026-69216 (GCVE-0-2026-69216)

Vulnerability from cvelistv5 – Published: 2026-09-15 18:59 – Updated: 2026-09-16 13:53

Title

Http4s: Ember chunk parser lenience (TE.TE request smuggling)

Summary

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

Severity

5.4 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-16 13:53 UTC

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

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/d78612a5a…	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": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-69216",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-16T13:53:39.504150Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-16T13:53:52.337Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "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, Ember\u2019s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. This issue is fixed in versions 0.23.35 and 1.0.0-M47."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-444",
              "description": "CWE-444: Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-15T18:59:50.609Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/http4s/http4s/security/advisories/GHSA-jrpm-956j-96jg",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/http4s/http4s/security/advisories/GHSA-jrpm-956j-96jg"
        },
        {
          "name": "https://github.com/http4s/http4s/commit/d78612a5abd5a2547487598d3342be05573e16f0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/http4s/commit/d78612a5abd5a2547487598d3342be05573e16f0"
        },
        {
          "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-jrpm-956j-96jg",
        "discovery": "UNKNOWN"
      },
      "title": "Http4s: Ember chunk parser lenience (TE.TE request smuggling)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-69216",
    "datePublished": "2026-09-15T18:59:50.609Z",
    "dateReserved": "2026-08-03T16:57:50.125Z",
    "dateUpdated": "2026-09-16T13:53:52.337Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-69216",
      "date": "2026-09-17",
      "epss": "0.00242",
      "percentile": "0.1555"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-69216\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-09-15T19:17:38.603\",\"lastModified\":\"2026-09-16T20:39:16.610\",\"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, Ember\u2019s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. 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:H/PR:N/UI:N/S:C/C:L/I:L/A:N\",\"baseScore\":5.4,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.2,\"impactScore\":2.7}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-09-16T13:53:39.504150Z\",\"id\":\"CVE-2026-69216\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-444\"}]}],\"references\":[{\"url\":\"https://github.com/http4s/http4s/commit/d78612a5abd5a2547487598d3342be05573e16f0\",\"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-jrpm-956j-96jg\",\"source\":\"security-advisories@github.com\"}]}}",
    "vulnrichment": {
      "containers": "{\"cna\": {\"title\": \"Http4s: Ember chunk parser lenience (TE.TE request smuggling)\", \"source\": {\"advisory\": \"GHSA-jrpm-956j-96jg\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"CHANGED\", \"version\": \"3.1\", \"baseScore\": 5.4, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N\", \"integrityImpact\": \"LOW\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"LOW\"}}], \"affected\": [{\"vendor\": \"http4s\", \"product\": \"http4s\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 0.23.35\"}, {\"status\": \"affected\", \"version\": \"\u003e= 1.0.0-M1, \u003c 1.0.0-M47\"}]}], \"references\": [{\"url\": \"https://github.com/http4s/http4s/security/advisories/GHSA-jrpm-956j-96jg\", \"name\": \"https://github.com/http4s/http4s/security/advisories/GHSA-jrpm-956j-96jg\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/http4s/http4s/commit/d78612a5abd5a2547487598d3342be05573e16f0\", \"name\": \"https://github.com/http4s/http4s/commit/d78612a5abd5a2547487598d3342be05573e16f0\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/http4s/http4s/releases/tag/v0.23.35\", \"name\": \"https://github.com/http4s/http4s/releases/tag/v0.23.35\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/http4s/http4s/releases/tag/v1.0.0-M47\", \"name\": \"https://github.com/http4s/http4s/releases/tag/v1.0.0-M47\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember\\u2019s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. This issue is fixed in versions 0.23.35 and 1.0.0-M47.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-444\", \"description\": \"CWE-444: Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-09-15T18:59:50.609Z\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-69216\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-09-16T13:53:39.504150Z\"}}}], \"providerMetadata\": {\"shortName\": \"CISA-ADP\", \"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"dateUpdated\": \"2026-09-16T13:53:46.246Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-69216\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-09-15T18:59:50.609Z\", \"dateReserved\": \"2026-08-03T16:57:50.125Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-09-15T18:59:50.609Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-69216

Vulnerability from fkie_nvd - Published: 2026-09-15 19:17 - Updated: 2026-09-16 20:39

Severity

5.4 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/http4s/http4s/commit/d78612a5abd5a2547487598d3342be05573e16f0
	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-jrpm-956j-96jg

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, Ember\u2019s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. This issue is fixed in versions 0.23.35 and 1.0.0-M47."
    }
  ],
  "id": "CVE-2026-69216",
  "lastModified": "2026-09-16T20:39:16.610",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.4,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 2.7,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-69216",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-16T13:53:39.504150Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-15T19:17:38.603",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/http4s/commit/d78612a5abd5a2547487598d3342be05573e16f0"
    },
    {
      "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-jrpm-956j-96jg"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-444"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-JRPM-956J-96JG

Vulnerability from github – Published: 2026-09-15 20:01 – Updated: 2026-09-15 20:01

Summary

Http4s: Ember chunk parser lenience (TE.TE request smuggling)

Details

Summary

Ember's chunk decoder parses the size token leniently: it strips leading and trailing whitespace and accepts a leading + or - sign. RFC9112 §7.1 defines chunk-size = 1*HEXDIG. An intermediary that parses the chunk boundary differently (or rejects it) will disagree with Ember on request framing, enabling HTTP request smuggling (TE.TE).

Impact

Server

Request smuggling (TE.TE) when ember-server is an origin behind an intermediary that forwards the body verbatim but interprets the malformed chunk sizes differently

Front-end security bypass: the smuggled request reaches paths the intermediary might have blocked, with attacker-chosen method and headers.
Cache poisoning: the smuggled response is associated with the next request key in a caching proxy.
Request queue hijack:

Client

ember-client has the same leniencies on the response path, which enables response smuggling when http4s is used as a gateway. This is less severe, as it requires a malicious or compromised upstream rather than an anonymous remote client.

Preconditions

Unauthenticated remote attacker (server)
ember-server as origin behind a keep-alive intermediary
Malicious or compromised upstream (client)
Intermediary or upstream forwards chunked bodies without re-encoding and disagrees with Ember on + prefix, - prefix, or leading and trailing octets rather than rejecting.

Workarounds

Intermediary strictly rejects malformed chunk sizes
Intermediary buffers and re-encodes request bodies

References

RFC9112 §7.1: Chunked Transfer Coding

Severity

5.4 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.23.34"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:http4s-ember-core_2.12"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.23.35"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.23.34"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:http4s-ember-core_2.13"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.23.35"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.23.34"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:http4s-ember-core_3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.23.35"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.0.0-M46"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:http4s-ember-core_2.13"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.0.0-M1"
            },
            {
              "fixed": "1.0.0-M47"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.0.0-M46"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:http4s-ember-core_3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.0.0-M1"
            },
            {
              "fixed": "1.0.0-M47"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-69216"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-15T20:01:00Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nEmber\u0027s chunk decoder parses the size token leniently: it strips leading and trailing whitespace and accepts a leading `+` or `-` sign.  RFC9112 \u00a77.1 defines `chunk-size = 1*HEXDIG`.  An intermediary that parses the chunk boundary differently (or rejects it) will disagree with Ember on request framing, enabling HTTP request smuggling (TE.TE).\n\n## Impact\n\n### Server\n\nRequest smuggling (TE.TE) when ember-server is an origin behind an intermediary that forwards the body verbatim but interprets the malformed chunk sizes differently\n\n- Front-end security bypass: the smuggled request reaches paths the intermediary might have blocked, with attacker-chosen method and headers.\n- Cache poisoning: the smuggled response is associated with the next request key in a caching proxy.\n- Request queue hijack:\n\n### Client\n\nember-client has the same leniencies on the response path, which enables response smuggling when http4s is used as a gateway.  This is less severe, as it requires a malicious or compromised upstream rather than an anonymous remote client.\n\n## Preconditions\n\n- Unauthenticated remote attacker (server)\n- ember-server as origin behind a keep-alive intermediary\n- Malicious or compromised upstream (client)\n- Intermediary or upstream forwards chunked bodies without re-encoding and disagrees with Ember on `+` prefix, `-` prefix, or leading and trailing octets rather than rejecting.\n\n## Workarounds\n\n- Intermediary strictly rejects malformed chunk sizes\n- Intermediary buffers and re-encodes request bodies\n\n## References\n\n- [RFC9112 \u00a77.1: Chunked Transfer Coding](https://www.rfc-editor.org/rfc/rfc9112.html#name-chunked-transfer-coding)",
  "id": "GHSA-jrpm-956j-96jg",
  "modified": "2026-09-15T20:01:00Z",
  "published": "2026-09-15T20:01:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/http4s/http4s/security/advisories/GHSA-jrpm-956j-96jg"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/http4s/commit/d78612a5abd5a2547487598d3342be05573e16f0"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/http4s/http4s"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/http4s/releases/tag/v0.23.35"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/http4s/releases/tag/v1.0.0-M47"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Http4s: Ember chunk parser lenience (TE.TE request smuggling)"
}

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.

Action not permitted

CVE-2026-69216 (GCVE-0-2026-69216)

FKIE_CVE-2026-69216

GHSA-JRPM-956J-96JG

Summary

Impact

Server

Client

Preconditions

Workarounds

References

Tags

Sightings

Nomenclature

Related by attack behaviour