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UnratedFix available

nginx: Fix of CVE-2026-56434

Type: advisorySources: OSV

- CVE-2026-56434: fix use-after-free in ngx_http_ssi_filter_module from duplicate subrequest finalization; ngx_http_post_request() now skips posting a request that is already queued, and ngx_http_finalize_request() resets r->write_event_handler to a no-op handler during active subrequest finalization

Products
nginx, nginx-all-modules, nginx-core, nginx-filesystem, nginx-mod-devel, nginx-mod-http-image-filter, nginx-mod-http-perl, nginx-mod-http-xslt-filter, nginx-mod-mail, nginx-mod-stream
Affected versions
Not specified
Fixed versions
1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14
CVEs
CVE-2026-56434
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 10:44 UTC · Revision 1

Source evidence

nginx: Fix of CVE-2026-56434

core-osv · Original source

Published 28 Aug 2026, 11:23 UTC

- CVE-2026-56434: fix use-after-free in ngx_http_ssi_filter_module from duplicate subrequest finalization; ngx_http_post_request() now skips posting a request that is already queued, and ngx_http_finalize_request() resets r->write_event_handler to a no-op handler during active subrequest finalization

osv:CLSA-2026-1787916225

nginx

Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14

nginx-all-modules

Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14

nginx-core

Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14

nginx-filesystem

Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14

nginx-mod-devel

Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14

nginx-mod-http-image-filter

Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14

nginx-mod-http-perl

Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14

nginx-mod-http-xslt-filter

Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14

nginx-mod-mail

Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14

nginx-mod-stream

Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14

Complete source record
{
  "id": "ff41622686364239595803c0e2eddd7734b1ed7fec0d2e780799a61712ea69c1",
  "url": "https://osv.dev/vulnerability/CLSA-2026-1787916225",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "nginx: Fix of CVE-2026-56434",
    "summary": "- CVE-2026-56434: fix use-after-free in ngx_http_ssi_filter_module from duplicate subrequest finalization; ngx_http_post_request() now skips posting a request that is already queued, and ngx_http_finalize_request() resets r->write_event_handler to a no-op handler during active subrequest finalization",
    "evidence": "osv:CLSA-2026-1787916225",
    "products": [
      {
        "name": {
          "value": "nginx",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nginx-all-modules",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nginx-core",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nginx-filesystem",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14",
            "evidence": "/affected/3/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nginx-mod-devel",
          "evidence": "/affected/4/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14",
            "evidence": "/affected/4/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nginx-mod-http-image-filter",
          "evidence": "/affected/5/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14",
            "evidence": "/affected/5/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nginx-mod-http-perl",
          "evidence": "/affected/6/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14",
            "evidence": "/affected/6/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nginx-mod-http-xslt-filter",
          "evidence": "/affected/7/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14",
            "evidence": "/affected/7/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nginx-mod-mail",
          "evidence": "/affected/8/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14",
            "evidence": "/affected/8/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "nginx-mod-stream",
          "evidence": "/affected/9/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14",
            "evidence": "/affected/9/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CLSA-2026-1787916225",
      "aliases": [
        "CLSA-2026-1787916225"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14"
                }
              ]
            }
          ],
          "package": {
            "name": "nginx",
            "purl": "pkg:rpm/tuxcare/nginx?distro=almalinux-9.2",
            "ecosystem": "TuxCare:AlmaLinux:9.2"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1787916225.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14"
                }
              ]
            }
          ],
          "package": {
            "name": "nginx-all-modules",
            "purl": "pkg:rpm/tuxcare/nginx-all-modules?distro=almalinux-9.2",
            "ecosystem": "TuxCare:AlmaLinux:9.2"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1787916225.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14"
                }
              ]
            }
          ],
          "package": {
            "name": "nginx-core",
            "purl": "pkg:rpm/tuxcare/nginx-core?distro=almalinux-9.2",
            "ecosystem": "TuxCare:AlmaLinux:9.2"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1787916225.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14"
                }
              ]
            }
          ],
          "package": {
            "name": "nginx-filesystem",
            "purl": "pkg:rpm/tuxcare/nginx-filesystem?distro=almalinux-9.2",
            "ecosystem": "TuxCare:AlmaLinux:9.2"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1787916225.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14"
                }
              ]
            }
          ],
          "package": {
            "name": "nginx-mod-devel",
            "purl": "pkg:rpm/tuxcare/nginx-mod-devel?distro=almalinux-9.2",
            "ecosystem": "TuxCare:AlmaLinux:9.2"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1787916225.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14"
                }
              ]
            }
          ],
          "package": {
            "name": "nginx-mod-http-image-filter",
            "purl": "pkg:rpm/tuxcare/nginx-mod-http-image-filter?distro=almalinux-9.2",
            "ecosystem": "TuxCare:AlmaLinux:9.2"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1787916225.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14"
                }
              ]
            }
          ],
          "package": {
            "name": "nginx-mod-http-perl",
            "purl": "pkg:rpm/tuxcare/nginx-mod-http-perl?distro=almalinux-9.2",
            "ecosystem": "TuxCare:AlmaLinux:9.2"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1787916225.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14"
                }
              ]
            }
          ],
          "package": {
            "name": "nginx-mod-http-xslt-filter",
            "purl": "pkg:rpm/tuxcare/nginx-mod-http-xslt-filter?distro=almalinux-9.2",
            "ecosystem": "TuxCare:AlmaLinux:9.2"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1787916225.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14"
                }
              ]
            }
          ],
          "package": {
            "name": "nginx-mod-mail",
            "purl": "pkg:rpm/tuxcare/nginx-mod-mail?distro=almalinux-9.2",
            "ecosystem": "TuxCare:AlmaLinux:9.2"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1787916225.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els14"
                }
              ]
            }
          ],
          "package": {
            "name": "nginx-mod-stream",
            "purl": "pkg:rpm/tuxcare/nginx-mod-stream?distro=almalinux-9.2",
            "ecosystem": "TuxCare:AlmaLinux:9.2"
          },
          "database_specific": {
            "source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1787916225.json"
          }
        }
      ],
      "modified": "2026-10-26T09:30:37.239766572Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-56434"
      ],
      "references": [
        "https://errata.tuxcare.com/els_os/almalinux9.2esu/CLSA-2026-1787916225.html",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-56434"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-56434",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 447167,
  "published_at": "2026-08-28T11:23:56+00:00"
}