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Critical

Apache HTTP Server: HTTP request splitting with mod_rewrite and mod_proxy

Type: advisorySources: OSV

Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack. Configurations are affected when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch in which a non-specific pattern matches some portion of the user-supplied request-target (URL) data and is then re-inserted into the proxied request-target using variable substitution. For example, something like: RewriteEngine on RewriteRule "^/here/(.*)" "http://example.com:8080/elsewhere?$1"; [P] ProxyPassReverse /here/ http://example.com:8080/ Request splitting/smuggling could result in bypass of access controls in the proxy server, proxying unintended URLs to existing origin servers, and cache poisoning. Users are recommended to update to at least version 2.4.56 of Apache HTTP Server.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2023-25690
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 17:12 UTC · Revision 1

Source evidence

Apache HTTP Server: HTTP request splitting with mod_rewrite and mod_proxy

core-osv · Original source

Published 7 Mar 2023, 15:09 UTC

Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack. Configurations are affected when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch in which a non-specific pattern matches some portion of the user-supplied request-target (URL) data and is then re-inserted into the proxied request-target using variable substitution. For example, something like: RewriteEngine on RewriteRule "^/here/(.*)" "http://example.com:8080/elsewhere?$1"; [P] ProxyPassReverse /here/ http://example.com:8080/ Request splitting/smuggling could result in bypass of access controls in the proxy server, proxying unintended URLs to existing origin servers, and cache poisoning. Users are recommended to update to at least version 2.4.56 of Apache HTTP Server.

osv:CVE-2023-25690
Complete source record
{
  "id": "e18aa86f2b22d03b23c5d6420503b27c8f7c5dda73c90d070cbc89c01f19042c",
  "url": "https://osv.dev/vulnerability/CVE-2023-25690",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Apache HTTP Server: HTTP request splitting with mod_rewrite and mod_proxy",
    "summary": "Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack. Configurations are affected when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch in which a non-specific pattern matches some portion of the user-supplied request-target (URL) data and is then re-inserted into the proxied request-target using variable substitution. For example, something like: RewriteEngine on RewriteRule \"^/here/(.*)\" \"http://example.com:8080/elsewhere?$1\"; [P] ProxyPassReverse /here/ http://example.com:8080/ Request splitting/smuggling could result in bypass of access controls in the proxy server, proxying unintended URLs to existing origin servers, and cache poisoning. Users are recommended to update to at least version 2.4.56 of Apache HTTP Server.",
    "evidence": "osv:CVE-2023-25690",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2023-25690",
      "aliases": [
        "BIT-apache-2023-25690",
        "CVE-2023-25690"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/apache/httpd",
              "type": "GIT",
              "events": [
                {
                  "introduced": "da5873e80d6eee7a0838793bf68f1d0254745fbb"
                },
                {
                  "last_affected": "8201e867f1d4cdf61840625c6c4be901e3f1b6ba"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.4.0"
                      },
                      {
                        "last_affected": "2.4.55"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-25690.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.585236407Z",
      "provider": "osv",
      "references": [
        "https://lists.debian.org/debian-lts-announce/2023/04/msg00028.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/25xxx/CVE-2023-25690.json",
        "https://httpd.apache.org/security/vulnerabilities_24.html",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-25690",
        "https://security.gentoo.org/glsa/202309-01"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-444"
        ],
        "cna_assigner": "apache",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "2.4.0"
                  },
                  {
                    "last_affected": "2.4.55"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/25xxx/CVE-2023-25690.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-25690",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 497737,
  "published_at": "2023-03-07T15:09:03.08+00:00"
}