Vulnerability-Lookup

UBUNTU-CVE-2026-84380 (CVE-2026-84380)

Vulnerability from osv_ubuntu – Published: 2026-09-02 18:21 – Updated: 2026-09-02 18:21 – Source website

Details

HTTPX2 is a next generation HTTP client for Python. Prior to 2.11.0, Request._prepare() in src/httpx2/httpx2/_models.py can add a body-derived Content-Length header to a request that already contains a caller-supplied Transfer-Encoding header because its setdefault() processing checks each default header independently rather than treating the two framing headers as mutually exclusive. Fixed-size byte, JSON, form, and known-length multipart bodies can therefore be serialized over HTTP/1.1 with both headers, allowing request smuggling or connection desynchronization when downstream intermediaries disagree about which framing header takes precedence. This issue is fixed in version 2.11.0.

Severity

5.6 (Medium)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-84380	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-84380	REPORT
	https://github.com/pydantic/httpx2/security/advis…	REPORT
	https://github.com/pydantic/httpx2/pull/1137	REPORT
	https://github.com/pydantic/httpx2/commit/829b93a…	REPORT
	https://github.com/pydantic/httpx2/releases/tag/v2.11.0	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-httpcore2",
            "binary_version": "2.5.0-1"
          },
          {
            "binary_name": "python3-httpx2",
            "binary_version": "2.5.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.10",
        "name": "python-httpx2",
        "purl": "pkg:deb/ubuntu/python-httpx2@2.5.0-1?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.5.0-1"
      ]
    }
  ],
  "aliases": [],
  "details": "HTTPX2 is a next generation HTTP client for Python. Prior to 2.11.0, Request._prepare() in src/httpx2/httpx2/_models.py can add a body-derived Content-Length header to a request that already contains a caller-supplied Transfer-Encoding header because its setdefault() processing checks each default header independently rather than treating the two framing headers as mutually exclusive. Fixed-size byte, JSON, form, and known-length multipart bodies can therefore be serialized over HTTP/1.1 with both headers, allowing request smuggling or connection desynchronization when downstream intermediaries disagree about which framing header takes precedence. This issue is fixed in version 2.11.0.",
  "id": "UBUNTU-CVE-2026-84380",
  "modified": "2026-09-02T18:21:00Z",
  "published": "2026-09-02T18:21:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-84380"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-84380"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pydantic/httpx2/security/advisories/GHSA-pf96-p4fj-6566"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pydantic/httpx2/pull/1137"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pydantic/httpx2/commit/829b93a2393212996f613e635261f777d9ec6eab"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pydantic/httpx2/releases/tag/v2.11.0"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-84380"
  ]
}

CVE-2026-84380 (GCVE-0-2026-84380)

Vulnerability from cvelistv5 – Published: 2026-09-02 17:58 – Updated: 2026-09-02 18:07

Title

HTTPX2: Conflicting Content-Length and Transfer-Encoding headers can be auto-generated

Summary

Severity

5.6 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-02 18:07 UTC

CWE

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

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7780 records in the last 180 days details

References

4 references

URL	Tags
https://github.com/pydantic/httpx2/security/advis…	x_refsource_CONFIRM
https://github.com/pydantic/httpx2/pull/1137	x_refsource_MISC
https://github.com/pydantic/httpx2/commit/829b93a…	x_refsource_MISC
https://github.com/pydantic/httpx2/releases/tag/v2.11.0	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
pydantic	httpx2	Affected: < 2.11.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-84380",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-02T18:07:09.850518Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-02T18:07:36.980Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "httpx2",
          "vendor": "pydantic",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.11.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "HTTPX2 is a next generation HTTP client for Python. Prior to 2.11.0, Request._prepare() in src/httpx2/httpx2/_models.py can add a body-derived Content-Length header to a request that already contains a caller-supplied Transfer-Encoding header because its setdefault() processing checks each default header independently rather than treating the two framing headers as mutually exclusive. Fixed-size byte, JSON, form, and known-length multipart bodies can therefore be serialized over HTTP/1.1 with both headers, allowing request smuggling or connection desynchronization when downstream intermediaries disagree about which framing header takes precedence. This issue is fixed in version 2.11.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5.6,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L",
            "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": "2026-09-02T17:58:55.520Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/pydantic/httpx2/security/advisories/GHSA-pf96-p4fj-6566",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/pydantic/httpx2/security/advisories/GHSA-pf96-p4fj-6566"
        },
        {
          "name": "https://github.com/pydantic/httpx2/pull/1137",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pydantic/httpx2/pull/1137"
        },
        {
          "name": "https://github.com/pydantic/httpx2/commit/829b93a2393212996f613e635261f777d9ec6eab",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pydantic/httpx2/commit/829b93a2393212996f613e635261f777d9ec6eab"
        },
        {
          "name": "https://github.com/pydantic/httpx2/releases/tag/v2.11.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pydantic/httpx2/releases/tag/v2.11.0"
        }
      ],
      "source": {
        "advisory": "GHSA-pf96-p4fj-6566",
        "discovery": "UNKNOWN"
      },
      "title": "HTTPX2: Conflicting Content-Length and Transfer-Encoding headers can be auto-generated"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-84380",
    "datePublished": "2026-09-02T17:58:55.520Z",
    "dateReserved": "2026-09-01T16:27:58.130Z",
    "dateUpdated": "2026-09-02T18:07:36.980Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Vulnerability timeline

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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.

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