Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2024-03-06 10:55

Modified

2026-09-08 08:34

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.

JSON

To clipboard

{
  "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": "2026-09-08T08:34:36.952Z",
  "published": "2024-03-06T10:55:51.283Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "http://httpd.apache.org/security/vulnerabilities_24.html"
    },
    {
      "type": "ADVISORY",
      "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": "ADVISORY",
      "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": "ADVISORY",
      "url": "https://seclists.org/oss-sec/2021/q2/206"
    },
    {
      "type": "ADVISORY",
      "url": "https://security.gentoo.org/glsa/202107-38"
    },
    {
      "type": "ADVISORY",
      "url": "https://security.netapp.com/advisory/ntap-20210727-0008/"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.debian.org/security/2021/dsa-4937"
    },
    {
      "type": "ADVISORY",
      "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"
}

CVE-2021-31618 (GCVE-0-2021-31618)

Vulnerability from cvelistv5 – Published: 2021-06-15 00:00 – Updated: 2024-08-03 23:03

Title

NULL pointer dereference on specially crafted HTTP/2 request

Summary

Severity

No CVSS data available.

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-05-20 16:18 UTC

CWE

CWE-476 - NULL Pointer Dereference

Assigner

apache mitre root

References

13 references

URL	Tags
http://httpd.apache.org/security/vulnerabilities_…
http://www.openwall.com/lists/oss-security/2021/06/10/9	mailing-list
https://seclists.org/oss-sec/2021/q2/206
https://lists.apache.org/thread.html/r14b66ef0f4f…	mailing-list
https://lists.apache.org/thread.html/r783b6558abf…	mailing-list
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisory
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisory
https://lists.debian.org/debian-lts-announce/2021…	mailing-list
https://www.debian.org/security/2021/dsa-4937	vendor-advisory
https://security.gentoo.org/glsa/202107-38	vendor-advisory
https://www.oracle.com/security-alerts/cpuoct2021.html
https://security.netapp.com/advisory/ntap-2021072…
http://www.openwall.com/lists/oss-security/2024/03/13/2	mailing-list

Impacted products

1 product

Vendor	Product	Version
Apache Software Foundation	Apache HTTP Server	Affected: 2.4.47

Credits

Apache HTTP server would like to thank LI ZHI XIN from NSFocus for reporting this.

Show details on NVD website

JSON

To clipboard

{
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}

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.

Related by attack behaviour

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