Vulnerability from bitnami_vulndb
Published
2024-03-06 10:55
Modified
2025-05-20 10:02
Summary
NULL pointer dereference on specially crafted HTTP/2 request
Details

Apache HTTP Server protocol handler for the HTTP/2 protocol checks received request headers against the size limitations as configured for the server and used for the HTTP/1 protocol as well. On violation of these restrictions and HTTP response is sent to the client with a status code indicating why the request was rejected. This rejection response was not fully initialised in the HTTP/2 protocol handler if the offending header was the very first one received or appeared in a a footer. This led to a NULL pointer dereference on initialised memory, crashing reliably the child process. Since such a triggering HTTP/2 request is easy to craft and submit, this can be exploited to DoS the server. This issue affected mod_http2 1.15.17 and Apache HTTP Server version 2.4.47 only. Apache HTTP Server 2.4.47 was never released.

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "apache",
        "purl": "pkg:bitnami/apache"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.15.17"
            },
            {
              "fixed": "1.15.18"
            },
            {
              "introduced": "2.4.47"
            },
            {
              "fixed": "2.4.48"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-31618"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:apache:http_server:1.15.17:*:*:*:*:*:*:*",
      "cpe:2.3:a:apache:http_server:2.4.47:*:*:*:*:*:*:*",
      "cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*"
    ],
    "severity": "High"
  },
  "details": "Apache HTTP Server protocol handler for the HTTP/2 protocol checks received request headers against the size limitations as configured for the server and used for the HTTP/1 protocol as well. On violation of these restrictions and HTTP response is sent to the client with a status code indicating why the request was rejected. This rejection response was not fully initialised in the HTTP/2 protocol handler if the offending header was the very first one received or appeared in a a footer. This led to a NULL pointer dereference on initialised memory, crashing reliably the child process. Since such a triggering HTTP/2 request is easy to craft and submit, this can be exploited to DoS the server. This issue affected mod_http2 1.15.17 and Apache HTTP Server version 2.4.47 only. Apache HTTP Server 2.4.47 was never released.",
  "id": "BIT-apache-2021-31618",
  "modified": "2025-05-20T10:02:07.006Z",
  "published": "2024-03-06T10:55:51.283Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://httpd.apache.org/security/vulnerabilities_24.html"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2021/06/10/9"
    },
    {
      "type": "WEB",
      "url": "https://lists.apache.org/thread.html/r14b66ef0f4f569fd515a3f96cd4eb58bd9a8ff525cc326bb0359664f%40%3Ccvs.httpd.apache.org%3E"
    },
    {
      "type": "WEB",
      "url": "https://lists.apache.org/thread.html/r783b6558abf3305b17ea462bed4bd66d82866438999bf38cef6d11d1%40%3Ccvs.httpd.apache.org%3E"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2021/07/msg00006.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2NKJ3ZA3FTSZ2QBBPKS6BYGAWYRABNQQ/"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A73QJ4HPUMU26I6EULG6SCK67TUEXZYR/"
    },
    {
      "type": "WEB",
      "url": "https://seclists.org/oss-sec/2021/q2/206"
    },
    {
      "type": "WEB",
      "url": "https://security.gentoo.org/glsa/202107-38"
    },
    {
      "type": "WEB",
      "url": "https://security.netapp.com/advisory/ntap-20210727-0008/"
    },
    {
      "type": "WEB",
      "url": "https://www.debian.org/security/2021/dsa-4937"
    },
    {
      "type": "WEB",
      "url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2024/03/13/2"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-31618"
    }
  ],
  "schema_version": "1.5.0",
  "summary": "NULL pointer dereference on specially crafted HTTP/2 request"
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • 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.