CVE-2026-86350 (GCVE-0-2026-86350)

Vulnerability from cvelistv5 – Published: 2026-09-23 11:31 – Updated: 2026-09-23 16:17
VLAI
Title
Apache Tomcat: Regression in fix for CVE-2026-41293 can trigger request header mix-up
Summary
Inconsistent interpretation of HTTP/2 requests ('HTTP Request/Response smuggling') vulnerability in Apache Tomcat caused by a regression in fix for CVE-2026-41293 can trigger request header mix-up. This issue affects Apache Tomcat: from 11.0.22 through 11.0.25, from 10.1.55 through 10.1.59, from 9.0.118 through 9.0.121. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
Severity
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-23 16:16 UTC
CWE
  • CWE-444 - Inconsistent interpretation of HTTP requests ('HTTP Request/Response smuggling')
Assigner
References
Impacted products
Vendor Product Version CPE status
Apache Software Foundation Apache Tomcat Affected: 11.0.22 , ≤ 11.0.25 (semver)
Affected: 10.1.55 , ≤ 10.1.59 (semver)
Affected: 9.0.118 , ≤ 9.0.121 (semver)
guessed Create a notification for this product.
Credits
Jeppe Weikop
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 9.1,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-86350",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-23T16:16:46.410403Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-23T16:17:11.408Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Apache Tomcat",
          "vendor": "Apache Software Foundation",
          "versions": [
            {
              "lessThanOrEqual": "11.0.25",
              "status": "affected",
              "version": "11.0.22",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "10.1.59",
              "status": "affected",
              "version": "10.1.55",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "9.0.121",
              "status": "affected",
              "version": "9.0.118",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Jeppe Weikop"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eInconsistent interpretation of HTTP/2 requests (\u0027HTTP Request/Response smuggling\u0027) vulnerability in Apache Tomcat caused by a\u0026nbsp;regression in fix for CVE-2026-41293 can trigger request header mix-up.\u003c/p\u003e\u003cp\u003eThis issue affects Apache Tomcat: from 11.0.22 through 11.0.25, from 10.1.55 through 10.1.59, from 9.0.118 through 9.0.121.\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/2 requests (\u0027HTTP Request/Response smuggling\u0027) vulnerability in Apache Tomcat caused by a\u00a0regression in fix for CVE-2026-41293 can trigger request header mix-up.\n\n\n\nThis issue affects Apache Tomcat: from 11.0.22 through 11.0.25, from 10.1.55 through 10.1.59, from 9.0.118 through 9.0.121.\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": "important"
            },
            "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": "2026-09-23T11:31:36.328Z",
        "orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
        "shortName": "apache"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://lists.apache.org/thread/mss45z99lcdd5dtpgcn45dy82f3toswc"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Apache Tomcat: Regression in fix for CVE-2026-41293 can trigger request header mix-up",
      "x_generator": {
        "engine": "Vulnogram 1.0.3"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
    "assignerShortName": "apache",
    "cveId": "CVE-2026-86350",
    "datePublished": "2026-09-23T11:31:36.328Z",
    "dateReserved": "2026-09-07T09:49:48.382Z",
    "dateUpdated": "2026-09-23T16:17:11.408Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-86350",
      "date": "2026-09-27",
      "epss": "0.00313",
      "percentile": "0.21714"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Apache Tomcat",
                "vendor": "Apache Software Foundation",
                "versions": [
                  {
                    "lessThanOrEqual": "11.0.25",
                    "status": "affected",
                    "version": "11.0.22",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "10.1.59",
                    "status": "affected",
                    "version": "10.1.55",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "9.0.121",
                    "status": "affected",
                    "version": "9.0.118",
                    "versionType": "semver"
                  }
                ]
              }
            ],
            "source": "security@apache.org"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Inconsistent interpretation of HTTP/2 requests (\u0027HTTP Request/Response smuggling\u0027) vulnerability in Apache Tomcat caused by a\u00a0regression in fix for CVE-2026-41293 can trigger request header mix-up.\n\n\n\nThis issue affects Apache Tomcat: from 11.0.22 through 11.0.25, from 10.1.55 through 10.1.59, from 9.0.118 through 9.0.121.\n\n\n\nUsers are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue."
          }
        ],
        "id": "CVE-2026-86350",
        "lastModified": "2026-09-23T17:58:26.570",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 9.1,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.2,
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-86350",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-23T16:16:46.410403Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-09-23T12:17:08.350",
        "references": [
          {
            "source": "security@apache.org",
            "url": "https://lists.apache.org/thread/mss45z99lcdd5dtpgcn45dy82f3toswc"
          }
        ],
        "sourceIdentifier": "security@apache.org",
        "vulnStatus": "Awaiting Analysis",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-444"
              }
            ],
            "source": "security@apache.org",
            "type": "Secondary"
          }
        ]
      }
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-25T23:52:53Z",
      "cve": "CVE-2026-86350",
      "id": "CVE-2026-86350",
      "initial_release_date": "2026-09-24T16:26:44Z",
      "product_status:known_affected": "497",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-86350",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-86350.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "cvssV3_1": {
                  "attackComplexity": "LOW",
                  "attackVector": "NETWORK",
                  "availabilityImpact": "NONE",
                  "baseScore": 9.1,
                  "baseSeverity": "CRITICAL",
                  "confidentialityImpact": "HIGH",
                  "integrityImpact": "HIGH",
                  "privilegesRequired": "NONE",
                  "scope": "UNCHANGED",
                  "userInteraction": "NONE",
                  "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                  "version": "3.1"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-86350",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-09-23T16:16:46.410403Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-09-23T16:16:39.762Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Apache Tomcat",
              "vendor": "Apache Software Foundation",
              "versions": [
                {
                  "lessThanOrEqual": "11.0.25",
                  "status": "affected",
                  "version": "11.0.22",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "10.1.59",
                  "status": "affected",
                  "version": "10.1.55",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "9.0.121",
                  "status": "affected",
                  "version": "9.0.118",
                  "versionType": "semver"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "finder",
              "value": "Jeppe Weikop"
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cp\u003eInconsistent interpretation of HTTP/2 requests (\u0027HTTP Request/Response smuggling\u0027) vulnerability in Apache Tomcat caused by a\u0026nbsp;regression in fix for CVE-2026-41293 can trigger request header mix-up.\u003c/p\u003e\u003cp\u003eThis issue affects Apache Tomcat: from 11.0.22 through 11.0.25, from 10.1.55 through 10.1.59, from 9.0.118 through 9.0.121.\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/2 requests (\u0027HTTP Request/Response smuggling\u0027) vulnerability in Apache Tomcat caused by a\u00a0regression in fix for CVE-2026-41293 can trigger request header mix-up.\n\n\n\nThis issue affects Apache Tomcat: from 11.0.22 through 11.0.25, from 10.1.55 through 10.1.59, from 9.0.118 through 9.0.121.\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": "important"
                },
                "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": "2026-09-23T11:31:36.328Z",
            "orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
            "shortName": "apache"
          },
          "references": [
            {
              "tags": [
                "vendor-advisory"
              ],
              "url": "https://lists.apache.org/thread/mss45z99lcdd5dtpgcn45dy82f3toswc"
            }
          ],
          "source": {
            "discovery": "EXTERNAL"
          },
          "title": "Apache Tomcat: Regression in fix for CVE-2026-41293 can trigger request header mix-up",
          "x_generator": {
            "engine": "Vulnogram 1.0.3"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
        "assignerShortName": "apache",
        "cveId": "CVE-2026-86350",
        "datePublished": "2026-09-23T11:31:36.328Z",
        "dateReserved": "2026-09-07T09:49:48.382Z",
        "dateUpdated": "2026-09-23T16:17:11.408Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.



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.