CVE-2026-43951 (GCVE-0-2026-43951)

Vulnerability from cvelistv5 – Published: 2026-06-08 15:16 – Updated: 2026-06-08 22:32
VLAI
Title
Apache HTTP Server: OOB Read in `merge_response_headers` can cause crash
Summary
Out-of-bounds Read vulnerability in Apache HTTP Server with mod_headers and mod_mime and multiple response languages. This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67.
Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-08 18:13 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version
Apache Software Foundation Apache HTTP Server Affected: 2.4.0 , ≤ 2.4.67 (semver)
Create a notification for this product.
Credits
Zhenpeng (Leo) Lin at depthfirst
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "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"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-43951",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-08T18:13:37.250801Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-08T18:14:03.963Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-06-08T22:32:28.584Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/06/08/10"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Apache HTTP Server",
          "vendor": "Apache Software Foundation",
          "versions": [
            {
              "lessThanOrEqual": "2.4.67",
              "status": "affected",
              "version": "2.4.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Zhenpeng (Leo) Lin at depthfirst"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eOut-of-bounds Read vulnerability in Apache HTTP Server with mod_headers and mod_mime and multiple response languages.\u003c/p\u003e\u003cp\u003eThis issue affects Apache HTTP Server: from 2.4.0 through 2.4.67."
            }
          ],
          "value": "Out-of-bounds Read vulnerability in Apache HTTP Server with mod_headers and mod_mime and multiple response languages.\n\nThis issue affects Apache HTTP Server: from 2.4.0 through 2.4.67."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "text": "moderate"
            },
            "type": "Textual description of severity"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-125",
              "description": "CWE-125 Out-of-bounds Read",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-08T15:16:14.594Z",
        "orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
        "shortName": "apache"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://httpd.apache.org/security/vulnerabilities_24.html"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "timeline": [
        {
          "lang": "en",
          "time": "2026-04-27T12:00:00.000Z",
          "value": "reported"
        },
        {
          "lang": "en",
          "time": "2026-06-05T12:00:00.000Z",
          "value": "fixed in 2.4.x by r1935006"
        },
        {
          "lang": "eng",
          "time": "2026-06-08T12:00:00.000Z",
          "value": "2.4.68 released"
        }
      ],
      "title": "Apache HTTP Server: OOB Read in `merge_response_headers` can cause crash",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
    "assignerShortName": "apache",
    "cveId": "CVE-2026-43951",
    "datePublished": "2026-06-08T15:16:14.594Z",
    "dateReserved": "2026-05-04T17:15:44.253Z",
    "dateUpdated": "2026-06-08T22:32:28.584Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-43951",
      "date": "2026-10-03",
      "epss": "0.01043",
      "percentile": "0.62867"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2026-06-08T22:32:28.584Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "url": "http://www.openwall.com/lists/oss-security/2026/06/08/10"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "metrics": [
              {
                "cvssV3_1": {
                  "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"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-43951",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-06-08T18:13:37.250801Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-06-08T18:13:58.958Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Apache HTTP Server",
              "vendor": "Apache Software Foundation",
              "versions": [
                {
                  "lessThanOrEqual": "2.4.67",
                  "status": "affected",
                  "version": "2.4.0",
                  "versionType": "semver"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "finder",
              "value": "Zhenpeng (Leo) Lin at depthfirst"
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cp\u003eOut-of-bounds Read vulnerability in Apache HTTP Server with mod_headers and mod_mime and multiple response languages.\u003c/p\u003e\u003cp\u003eThis issue affects Apache HTTP Server: from 2.4.0 through 2.4.67."
                }
              ],
              "value": "Out-of-bounds Read vulnerability in Apache HTTP Server with mod_headers and mod_mime and multiple response languages.\n\nThis issue affects Apache HTTP Server: from 2.4.0 through 2.4.67."
            }
          ],
          "metrics": [
            {
              "other": {
                "content": {
                  "text": "moderate"
                },
                "type": "Textual description of severity"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-125",
                  "description": "CWE-125 Out-of-bounds Read",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-06-08T15:16:14.594Z",
            "orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
            "shortName": "apache"
          },
          "references": [
            {
              "tags": [
                "vendor-advisory"
              ],
              "url": "https://httpd.apache.org/security/vulnerabilities_24.html"
            }
          ],
          "source": {
            "discovery": "UNKNOWN"
          },
          "timeline": [
            {
              "lang": "en",
              "time": "2026-04-27T12:00:00.000Z",
              "value": "reported"
            },
            {
              "lang": "en",
              "time": "2026-06-05T12:00:00.000Z",
              "value": "fixed in 2.4.x by r1935006"
            },
            {
              "lang": "eng",
              "time": "2026-06-08T12:00:00.000Z",
              "value": "2.4.68 released"
            }
          ],
          "title": "Apache HTTP Server: OOB Read in `merge_response_headers` can cause crash",
          "x_generator": {
            "engine": "Vulnogram 0.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
        "assignerShortName": "apache",
        "cveId": "CVE-2026-43951",
        "datePublished": "2026-06-08T15:16:14.594Z",
        "dateReserved": "2026-05-04T17:15:44.253Z",
        "dateUpdated": "2026-06-08T22:32:28.584Z",
        "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.


Detection rules are retrieved from Rulezet.


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.