Vulnerability-Lookup

CVE-2026-93566 (GCVE-0-2026-93566)

Vulnerability from cvelistv5 – Published: 2026-09-18 14:19 – Updated: 2026-09-18 20:12

Title

Io.netty/netty-codec-http: netty: http request smuggling due to control characters in the chunk-size line

Summary

A flaw was found in Netty. A remote attacker could exploit this by sending a specially crafted HTTP request that includes control characters within the chunk-size line. This bypasses the intended strict validation, allowing the attacker to inject arbitrary HTTP requests. This vulnerability can lead to HTTP request smuggling, potentially resulting in information disclosure or other unauthorized actions.

Severity

6.5 (Medium)


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

CWE

CWE-1035

Assigner

redhat redhat root

References

2 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-93566	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2536954	issue-trackingx_refsource_REDHAT

Impacted products

13 products

Vendor	Product	Version
Red Hat	Red Hat AMQ Broker 7	cpe:/a:redhat:amq_broker:7
Red Hat	Red Hat AMQ Clients	cpe:/a:redhat:amq_clients:2023
Red Hat	Red Hat build of Apache Camel 4 for Quarkus 3	cpe:/a:redhat:camel_quarkus:3
Red Hat	Red Hat build of Apache Camel for Spring Boot 4	cpe:/a:redhat:camel_spring_boot:4
Red Hat	Red Hat build of Apicurio Registry 3	cpe:/a:redhat:apicurio_registry:3
Red Hat	Red Hat build of Debezium 3	cpe:/a:redhat:debezium:3
Red Hat	Red Hat Build of Keycloak	cpe:/a:redhat:build_keycloak:
Red Hat	Red Hat build of Quarkus	cpe:/a:redhat:quarkus:3
Red Hat	Red Hat Data Grid 8	cpe:/a:redhat:jboss_data_grid:8
Red Hat	Red Hat Fuse 7	cpe:/a:redhat:jboss_fuse:7
Red Hat	Red Hat JBoss Enterprise Application Platform 7	cpe:/a:redhat:jboss_enterprise_application_platform:7
Red Hat	Red Hat JBoss Enterprise Application Platform 8	cpe:/a:redhat:jboss_enterprise_application_platform:8
Red Hat	Red Hat Single Sign-On 7	cpe:/a:redhat:red_hat_single_sign_on:7

Date Public

2026-09-10 00:47

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-93566

Vulnerability from fkie_nvd - Published: 2026-09-18 15:17 - Updated: 2026-09-18 21:18

Severity

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

Summary

References

	URL	Tags
	secalert@redhat.com	https://access.redhat.com/security/cve/CVE-2026-93566
	secalert@redhat.com	https://bugzilla.redhat.com/show_bug.cgi?id=2536954

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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  ],
  "id": "CVE-2026-93566",
  "lastModified": "2026-09-18T21:18:47.507",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 2.5,
        "source": "secalert@redhat.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-18T15:17:20.290",
  "references": [
    {
      "source": "secalert@redhat.com",
      "url": "https://access.redhat.com/security/cve/CVE-2026-93566"
    },
    {
      "source": "secalert@redhat.com",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2536954"
    }
  ],
  "sourceIdentifier": "secalert@redhat.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-1035"
        }
      ],
      "source": "secalert@redhat.com",
      "type": "Secondary"
    }
  ]
}

GHSA-9MRJ-55P4-QWF4

Vulnerability from github – Published: 2026-09-18 15:32 – Updated: 2026-09-18 15:32

Details

Summary

Netty skips strict chunk size line validation when the line has no chunk extension (;), so a chunk size line containing an embedded bare CR (e.g. 0\rX) is accepted instead of rejected, enabling HTTP request smuggling.

Details

io.netty.handler.codec.http.HttpObjectDecoder#checkChunkExtensions only runs the strict validator HttpChunkLineValidatingByteProcessor when a ; is present:

        int extensionsStart = line.bytesBefore((byte) ';');
        if (extensionsStart == -1) {
            return;
        }

According to RFC 9112 https://datatracker.ietf.org/doc/html/rfc9112#appendix-A

chunk-size = 1*HEXDIG

PoC

```java @Test public void test() { String requestStr = "POST / HTTP/1.1\r\n" + "Host: localhost\r\n" + "Transfer-Encoding: chunked\r\n\r\n" + "0\rX\r\n" + "\r\n" + "GET /smuggled HTTP/1.1\r\n" + "Host: localhost\r\n" + "Content-Length: 0\r\n" + "\r\n";

EmbeddedChannel channel = new EmbeddedChannel(new HttpRequestDecoder());
assertTrue(channel.writeInbound(Unpooled.copiedBuffer(requestStr, Ch

Severity

6.5 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-93566"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-18T15:17:20Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\nNetty skips strict chunk size line validation when the line has no chunk extension (`;`), so a chunk size line containing an embedded bare CR (e.g. `0\\rX`) is accepted instead of rejected, enabling HTTP request smuggling.\n\n### Details\n`io.netty.handler.codec.http.HttpObjectDecoder#checkChunkExtensions` only runs the strict validator `HttpChunkLineValidatingByteProcessor` when a `;` is present:\n\n```java\n        int extensionsStart = line.bytesBefore((byte) \u0027;\u0027);\n        if (extensionsStart == -1) {\n            return;\n        }\n```\n\nAccording to RFC 9112 https://datatracker.ietf.org/doc/html/rfc9112#appendix-A\n\n`chunk-size = 1*HEXDIG`\n\n### PoC\n\n```java\n@Test\npublic void test() {\n    String requestStr = \"POST / HTTP/1.1\\r\\n\" +\n            \"Host: localhost\\r\\n\" +\n            \"Transfer-Encoding: chunked\\r\\n\\r\\n\" +\n            \"0\\rX\\r\\n\" +\n            \"\\r\\n\" +\n            \"GET /smuggled HTTP/1.1\\r\\n\" +\n            \"Host: localhost\\r\\n\" +\n            \"Content-Length: 0\\r\\n\" +\n            \"\\r\\n\";\n\n    EmbeddedChannel channel = new EmbeddedChannel(new HttpRequestDecoder());\n    assertTrue(channel.writeInbound(Unpooled.copiedBuffer(requestStr, Ch",
  "id": "GHSA-9mrj-55p4-qwf4",
  "modified": "2026-09-18T15:32:20Z",
  "published": "2026-09-18T15:32:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93566"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-93566"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2536954"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

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.

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Action not permitted

CVE-2026-93566 (GCVE-0-2026-93566)

FKIE_CVE-2026-93566

GHSA-9MRJ-55P4-QWF4

Summary

Details

PoC

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