CVE-2026-77756 (GCVE-0-2026-77756)
Vulnerability from cvelistv5
Published
2026-09-23 11:18
Modified
2026-09-23 18:10
Severity ?
CWE
  • CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Summary
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Apache Tomcat caused by processing the transfer-encoding header for an HTTP/1.0 request may allow an attacker to cause one request from another user to fail when Tomcat is located behind a reverse proxy. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.47 through 9.0.121. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.67 through 8.5.100. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
References
Impacted products
Vendor Product Version
Apache Software Foundation Apache Tomcat Version: 11.0.0-M1   ≤ 11.0.25
Version: 10.1.0-M1   ≤ 10.1.59
Version: 9.0.47   ≤ 9.0.121
Version: 8.5.67   ≤ 8.5.100
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "HIGH",
              "attackVector": "NETWORK",
              "availabilityImpact": "LOW",
              "baseScore": 3.7,
              "baseSeverity": "LOW",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-77756",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-23T13:18:16.430403Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-23T13:18:19.230Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-09-23T18:10:42.842Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/09/23/22"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Apache Tomcat",
          "vendor": "Apache Software Foundation",
          "versions": [
            {
              "lessThanOrEqual": "11.0.25",
              "status": "affected",
              "version": "11.0.0-M1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "10.1.59",
              "status": "affected",
              "version": "10.1.0-M1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "9.0.121",
              "status": "affected",
              "version": "9.0.47",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "8.5.100",
              "status": "affected",
              "version": "8.5.67",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.109",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eInconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027) vulnerability in Apache Tomcat caused by processing the transfer-encoding header for an HTTP/1.0 request may allow an attacker to cause one request from another user to fail when Tomcat is located behind a reverse proxy.\u003c/p\u003e\u003cp\u003eThis issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.47 through 9.0.121.\u003c/p\u003e\u003cp\u003eThe following versions were EOL at the time the CVE was created but are \nknown to be affected: from 8.5.67 through 8.5.100. Other unsupported versions may also be affected.\u003c/p\u003e\u003cp\u003eUsers are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.\u003c/p\u003e"
            }
          ],
          "value": "Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027) vulnerability in Apache Tomcat caused by processing the transfer-encoding header for an HTTP/1.0 request may allow an attacker to cause one request from another user to fail when Tomcat is located behind a reverse proxy.\n\n\n\nThis issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.47 through 9.0.121.\n\n\n\nThe following versions were EOL at the time the CVE was created but are \nknown to be affected: from 8.5.67 through 8.5.100. Other unsupported versions may also be affected.\n\n\n\nUsers are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "text": "low"
            },
            "type": "Textual description of severity"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-444",
              "description": "CWE-444 Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-23T11:18:02.672Z",
        "orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
        "shortName": "apache"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://lists.apache.org/thread/bl5b6rxqh3vb2k9bj2794vhor7o6xl3z"
        }
      ],
      "source": {
        "discovery": "INTERNAL"
      },
      "title": "Apache Tomcat: Transfer-Encoding honored for HTTP/1.0 requests",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
    "assignerShortName": "apache",
    "cveId": "CVE-2026-77756",
    "datePublished": "2026-09-23T11:18:02.672Z",
    "dateReserved": "2026-08-21T09:55:42.227Z",
    "dateUpdated": "2026-09-23T18:10:42.842Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"http://www.openwall.com/lists/oss-security/2026/09/23/22\"}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2026-09-23T18:10:42.842Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 3.7, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"LOW\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"LOW\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-77756\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-09-23T13:18:16.430403Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-09-23T13:18:12.690Z\"}}], \"cna\": {\"title\": \"Apache Tomcat: Transfer-Encoding honored for HTTP/1.0 requests\", \"source\": {\"discovery\": \"INTERNAL\"}, \"metrics\": [{\"other\": {\"type\": \"Textual description of severity\", \"content\": {\"text\": \"low\"}}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"Apache Software Foundation\", \"product\": \"Apache Tomcat\", \"versions\": [{\"status\": \"affected\", \"version\": \"11.0.0-M1\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"11.0.25\"}, {\"status\": \"affected\", \"version\": \"10.1.0-M1\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"10.1.59\"}, {\"status\": \"affected\", \"version\": \"9.0.47\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"9.0.121\"}, {\"status\": \"affected\", \"version\": \"8.5.67\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"8.5.100\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"7.0.109\"}], \"defaultStatus\": \"unaffected\"}], \"references\": [{\"url\": \"https://lists.apache.org/thread/bl5b6rxqh3vb2k9bj2794vhor7o6xl3z\", \"tags\": [\"vendor-advisory\"]}], \"x_generator\": {\"engine\": \"Vulnogram 0.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027) vulnerability in Apache Tomcat caused by processing the transfer-encoding header for an HTTP/1.0 request may allow an attacker to cause one request from another user to fail when Tomcat is located behind a reverse proxy.\\n\\n\\n\\nThis issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.47 through 9.0.121.\\n\\n\\n\\nThe following versions were EOL at the time the CVE was created but are \\nknown to be affected: from 8.5.67 through 8.5.100. Other unsupported versions may also be affected.\\n\\n\\n\\nUsers are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003eInconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027) vulnerability in Apache Tomcat caused by processing the transfer-encoding header for an HTTP/1.0 request may allow an attacker to cause one request from another user to fail when Tomcat is located behind a reverse proxy.\u003c/p\u003e\u003cp\u003eThis issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.47 through 9.0.121.\u003c/p\u003e\u003cp\u003eThe following versions were EOL at the time the CVE was created but are \\nknown to be affected: from 8.5.67 through 8.5.100. Other unsupported versions may also be affected.\u003c/p\u003e\u003cp\u003eUsers are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.\u003c/p\u003e\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-444\", \"description\": \"CWE-444 Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)\"}]}], \"providerMetadata\": {\"orgId\": \"f0158376-9dc2-43b6-827c-5f631a4d8d09\", \"shortName\": \"apache\", \"dateUpdated\": \"2026-09-23T11:18:02.672Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-77756\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-09-23T18:10:42.842Z\", \"dateReserved\": \"2026-08-21T09:55:42.227Z\", \"assignerOrgId\": \"f0158376-9dc2-43b6-827c-5f631a4d8d09\", \"datePublished\": \"2026-09-23T11:18:02.672Z\", \"assignerShortName\": \"apache\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.