Vulnerability-Lookup

OESA-2026-2587 (CVE-2026-9256)

Vulnerability from osv_openeuler – Published: 2026-06-05 11:11 – Updated: 2026-08-06 11:11 – Source website

Summary

nginx security update

Details

NGINX is a free, open-source, high-performance HTTP server and reverse proxy, as well as an IMAP/POP3 proxy server.

Security Fix(es):

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.(CVE-2026-9256)

Severity

8.1 (High)


                    
                      CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

URL

Type

	https://www.openeuler.org/zh/security/security-bu…	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2026-9256	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "aarch64": [
          "nginx-1.21.5-15.oe2203sp4.aarch64.rpm",
          "nginx-debuginfo-1.21.5-15.oe2203sp4.aarch64.rpm",
          "nginx-debugsource-1.21.5-15.oe2203sp4.aarch64.rpm",
          "nginx-mod-devel-1.21.5-15.oe2203sp4.aarch64.rpm",
          "nginx-mod-http-image-filter-1.21.5-15.oe2203sp4.aarch64.rpm",
          "nginx-mod-http-perl-1.21.5-15.oe2203sp4.aarch64.rpm",
          "nginx-mod-http-xslt-filter-1.21.5-15.oe2203sp4.aarch64.rpm",
          "nginx-mod-mail-1.21.5-15.oe2203sp4.aarch64.rpm",
          "nginx-mod-stream-1.21.5-15.oe2203sp4.aarch64.rpm"
        ],
        "noarch": [
          "nginx-all-modules-1.21.5-15.oe2203sp4.noarch.rpm",
          "nginx-filesystem-1.21.5-15.oe2203sp4.noarch.rpm",
          "nginx-help-1.21.5-15.oe2203sp4.noarch.rpm"
        ],
        "src": [
          "nginx-1.21.5-15.oe2203sp4.src.rpm"
        ],
        "x86_64": [
          "nginx-1.21.5-15.oe2203sp4.x86_64.rpm",
          "nginx-debuginfo-1.21.5-15.oe2203sp4.x86_64.rpm",
          "nginx-debugsource-1.21.5-15.oe2203sp4.x86_64.rpm",
          "nginx-mod-devel-1.21.5-15.oe2203sp4.x86_64.rpm",
          "nginx-mod-http-image-filter-1.21.5-15.oe2203sp4.x86_64.rpm",
          "nginx-mod-http-perl-1.21.5-15.oe2203sp4.x86_64.rpm",
          "nginx-mod-http-xslt-filter-1.21.5-15.oe2203sp4.x86_64.rpm",
          "nginx-mod-mail-1.21.5-15.oe2203sp4.x86_64.rpm",
          "nginx-mod-stream-1.21.5-15.oe2203sp4.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:22.03-LTS-SP4",
        "name": "nginx",
        "purl": "pkg:rpm/openEuler/nginx\u0026distro=openEuler-22.03-LTS-SP4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.21.5-15.oe2203sp4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "aarch64": [
          "nginx-1.24.0-11.oe2403sp1.aarch64.rpm",
          "nginx-debuginfo-1.24.0-11.oe2403sp1.aarch64.rpm",
          "nginx-debugsource-1.24.0-11.oe2403sp1.aarch64.rpm",
          "nginx-mod-devel-1.24.0-11.oe2403sp1.aarch64.rpm",
          "nginx-mod-http-image-filter-1.24.0-11.oe2403sp1.aarch64.rpm",
          "nginx-mod-http-perl-1.24.0-11.oe2403sp1.aarch64.rpm",
          "nginx-mod-http-xslt-filter-1.24.0-11.oe2403sp1.aarch64.rpm",
          "nginx-mod-mail-1.24.0-11.oe2403sp1.aarch64.rpm",
          "nginx-mod-stream-1.24.0-11.oe2403sp1.aarch64.rpm",
          "compat-nginx-1.24.0-11.oe2403sp1.aarch64.rpm",
          "compat-nginx-debuginfo-1.24.0-11.oe2403sp1.aarch64.rpm",
          "compat-nginx-debugsource-1.24.0-11.oe2403sp1.aarch64.rpm",
          "compat-nginx-mod-http-image-filter-1.24.0-11.oe2403sp1.aarch64.rpm",
          "compat-nginx-mod-http-perl-1.24.0-11.oe2403sp1.aarch64.rpm",
          "compat-nginx-mod-http-xslt-filter-1.24.0-11.oe2403sp1.aarch64.rpm",
          "compat-nginx-mod-mail-1.24.0-11.oe2403sp1.aarch64.rpm",
          "compat-nginx-mod-stream-1.24.0-11.oe2403sp1.aarch64.rpm"
        ],
        "noarch": [
          "nginx-all-modules-1.24.0-11.oe2403sp1.noarch.rpm",
          "nginx-filesystem-1.24.0-11.oe2403sp1.noarch.rpm",
          "nginx-help-1.24.0-11.oe2403sp1.noarch.rpm",
          "compat-nginx-all-modules-1.24.0-11.oe2403sp1.noarch.rpm",
          "compat-nginx-filesystem-1.24.0-11.oe2403sp1.noarch.rpm",
          "compat-nginx-help-1.24.0-11.oe2403sp1.noarch.rpm"
        ],
        "src": [
          "nginx-1.24.0-11.oe2403sp1.src.rpm",
          "compat-nginx-1.24.0-11.oe2403sp1.src.rpm"
        ],
        "x86_64": [
          "nginx-1.24.0-11.oe2403sp1.x86_64.rpm",
          "nginx-debuginfo-1.24.0-11.oe2403sp1.x86_64.rpm",
          "nginx-debugsource-1.24.0-11.oe2403sp1.x86_64.rpm",
          "nginx-mod-devel-1.24.0-11.oe2403sp1.x86_64.rpm",
          "nginx-mod-http-image-filter-1.24.0-11.oe2403sp1.x86_64.rpm",
          "nginx-mod-http-perl-1.24.0-11.oe2403sp1.x86_64.rpm",
          "nginx-mod-http-xslt-filter-1.24.0-11.oe2403sp1.x86_64.rpm",
          "nginx-mod-mail-1.24.0-11.oe2403sp1.x86_64.rpm",
          "nginx-mod-stream-1.24.0-11.oe2403sp1.x86_64.rpm",
          "compat-nginx-1.24.0-11.oe2403sp1.x86_64.rpm",
          "compat-nginx-debuginfo-1.24.0-11.oe2403sp1.x86_64.rpm",
          "compat-nginx-debugsource-1.24.0-11.oe2403sp1.x86_64.rpm",
          "compat-nginx-mod-http-image-filter-1.24.0-11.oe2403sp1.x86_64.rpm",
          "compat-nginx-mod-http-perl-1.24.0-11.oe2403sp1.x86_64.rpm",
          "compat-nginx-mod-http-xslt-filter-1.24.0-11.oe2403sp1.x86_64.rpm",
          "compat-nginx-mod-mail-1.24.0-11.oe2403sp1.x86_64.rpm",
          "compat-nginx-mod-stream-1.24.0-11.oe2403sp1.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:24.03-LTS-SP1",
        "name": "nginx",
        "purl": "pkg:rpm/openEuler/nginx\u0026distro=openEuler-24.03-LTS-SP1"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "compat-1.24.0-11.oe2403sp1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "aarch64": [
          "nginx-1.24.0-11.oe2403sp3.aarch64.rpm",
          "nginx-debuginfo-1.24.0-11.oe2403sp3.aarch64.rpm",
          "nginx-debugsource-1.24.0-11.oe2403sp3.aarch64.rpm",
          "nginx-mod-devel-1.24.0-11.oe2403sp3.aarch64.rpm",
          "nginx-mod-http-image-filter-1.24.0-11.oe2403sp3.aarch64.rpm",
          "nginx-mod-http-perl-1.24.0-11.oe2403sp3.aarch64.rpm",
          "nginx-mod-http-xslt-filter-1.24.0-11.oe2403sp3.aarch64.rpm",
          "nginx-mod-mail-1.24.0-11.oe2403sp3.aarch64.rpm",
          "nginx-mod-stream-1.24.0-11.oe2403sp3.aarch64.rpm"
        ],
        "noarch": [
          "nginx-all-modules-1.24.0-11.oe2403sp3.noarch.rpm",
          "nginx-filesystem-1.24.0-11.oe2403sp3.noarch.rpm",
          "nginx-help-1.24.0-11.oe2403sp3.noarch.rpm"
        ],
        "src": [
          "nginx-1.24.0-11.oe2403sp3.src.rpm"
        ],
        "x86_64": [
          "nginx-1.24.0-11.oe2403sp3.x86_64.rpm",
          "nginx-debuginfo-1.24.0-11.oe2403sp3.x86_64.rpm",
          "nginx-debugsource-1.24.0-11.oe2403sp3.x86_64.rpm",
          "nginx-mod-devel-1.24.0-11.oe2403sp3.x86_64.rpm",
          "nginx-mod-http-image-filter-1.24.0-11.oe2403sp3.x86_64.rpm",
          "nginx-mod-http-perl-1.24.0-11.oe2403sp3.x86_64.rpm",
          "nginx-mod-http-xslt-filter-1.24.0-11.oe2403sp3.x86_64.rpm",
          "nginx-mod-mail-1.24.0-11.oe2403sp3.x86_64.rpm",
          "nginx-mod-stream-1.24.0-11.oe2403sp3.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:24.03-LTS-SP3",
        "name": "nginx",
        "purl": "pkg:rpm/openEuler/nginx\u0026distro=openEuler-24.03-LTS-SP3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.24.0-11.oe2403sp3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "aarch64": [
          "nginx-1.21.5-13.oe2003sp4.aarch64.rpm",
          "nginx-debuginfo-1.21.5-13.oe2003sp4.aarch64.rpm",
          "nginx-debugsource-1.21.5-13.oe2003sp4.aarch64.rpm",
          "nginx-mod-devel-1.21.5-13.oe2003sp4.aarch64.rpm",
          "nginx-mod-http-image-filter-1.21.5-13.oe2003sp4.aarch64.rpm",
          "nginx-mod-http-perl-1.21.5-13.oe2003sp4.aarch64.rpm",
          "nginx-mod-http-xslt-filter-1.21.5-13.oe2003sp4.aarch64.rpm",
          "nginx-mod-mail-1.21.5-13.oe2003sp4.aarch64.rpm",
          "nginx-mod-stream-1.21.5-13.oe2003sp4.aarch64.rpm"
        ],
        "noarch": [
          "nginx-all-modules-1.21.5-13.oe2003sp4.noarch.rpm",
          "nginx-filesystem-1.21.5-13.oe2003sp4.noarch.rpm"
        ],
        "src": [
          "nginx-1.21.5-13.oe2003sp4.src.rpm"
        ],
        "x86_64": [
          "nginx-1.21.5-13.oe2003sp4.x86_64.rpm",
          "nginx-debuginfo-1.21.5-13.oe2003sp4.x86_64.rpm",
          "nginx-debugsource-1.21.5-13.oe2003sp4.x86_64.rpm",
          "nginx-mod-devel-1.21.5-13.oe2003sp4.x86_64.rpm",
          "nginx-mod-http-image-filter-1.21.5-13.oe2003sp4.x86_64.rpm",
          "nginx-mod-http-perl-1.21.5-13.oe2003sp4.x86_64.rpm",
          "nginx-mod-http-xslt-filter-1.21.5-13.oe2003sp4.x86_64.rpm",
          "nginx-mod-mail-1.21.5-13.oe2003sp4.x86_64.rpm",
          "nginx-mod-stream-1.21.5-13.oe2003sp4.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:20.03-LTS-SP4",
        "name": "nginx",
        "purl": "pkg:rpm/openEuler/nginx\u0026distro=openEuler-20.03-LTS-SP4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.21.5-13.oe2003sp4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "High"
  },
  "details": "NGINX is a free, open-source, high-performance HTTP server and reverse proxy,  as well as an IMAP/POP3 proxy server.\r\n\r\nSecurity Fix(es):\n\nNGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated.(CVE-2026-9256)",
  "id": "OESA-2026-2587",
  "modified": "2026-08-06T11:11:31Z",
  "published": "2026-06-05T11:11:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-2587"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9256"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "nginx security update",
  "upstream": [
    "CVE-2026-9256"
  ]
}

CVE-2026-9256 (GCVE-0-2026-9256)

Vulnerability from cvelistv5 – Published: 2026-05-22 14:11 – Updated: 2026-08-25 12:05 X_F5

Title

NGINX ngx_http_rewrite_module vulnerability

Summary

Severity

8.1 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

9.2 (Critical)


                        
                          CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-22 00:00 UTC

CWE

CWE-122 - Heap-based Buffer Overflow

Assigner

f5 mitre root

References

15 references

URL	Tags
https://my.f5.com/manage/s/article/K000161377	vendor-advisory
http://www.openwall.com/lists/oss-security/2026/0…
https://lists.debian.org/debian-lts-announce/2026…
https://access.redhat.com/security/cve/CVE-2026-9256	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2480746	issue-trackingx_refsource_REDHAT
https://security.access.redhat.com/data/csaf/v2/v…	x_sadp-csaf-vex
https://access.redhat.com/errata/RHSA-2026:29874	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:28921	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:28212	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:28973	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:29151	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:33313	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:20351	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:44481	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:58981	vendor-advisoryx_refsource_REDHAT

Impacted products

15 products

Vendor	Product	Version
F5	NGINX Plus	Affected: 37.0 , < 37.0.1.1 (custom) Affected: R36 , < R36 P5 (custom) Affected: R32 , < R32 P7 (custom)
F5	NGINX Open Source	Affected: 1.31.0 , < 1.31.1 (custom) Affected: 1.30.0 , < 1.30.2 (custom) Affected: 0.1.17 , ≤ 0.9.7 (custom)
Red Hat	Red Hat Enterprise Linux 10	Unaffected: 2:1.26.3-6.el10_2.4 , < * (rpm) cpe:/o:redhat:enterprise_linux:10.2
Red Hat	Red Hat Enterprise Linux 8	Unaffected: 8100020260611094050.489197e6 , < * (rpm) cpe:/a:redhat:enterprise_linux:8
Red Hat	Red Hat Enterprise Linux 9	Unaffected: 9080020260610161820.9 , < * (rpm) cpe:/a:redhat:enterprise_linux:9
Red Hat	Red Hat Enterprise Linux 9	Unaffected: 2:1.20.1-28.el9_8.3 , < * (rpm) cpe:/a:redhat:enterprise_linux:9
Red Hat	Red Hat Enterprise Linux 9	Unaffected: 9080020260609152155.9 , < * (rpm) cpe:/a:redhat:enterprise_linux:9
Red Hat	Red Hat Discovery 2	Unaffected: 1782756541 , < * (rpm) cpe:/a:redhat:discovery:2::el9
Red Hat	Red Hat Hardened Images	Unaffected: 1.30.2-1.hum1 , < * (rpm) cpe:/a:redhat:hummingbird:1
Red Hat	Red Hat Update Infrastructure 5	Unaffected: 1784794818 , < * (rpm) cpe:/a:redhat:rhui:5::el9
Red Hat	Red Hat Update Infrastructure 5	Unaffected: 1784794778 , < * (rpm) cpe:/a:redhat:rhui:5::el9
Red Hat	Red Hat Update Infrastructure 5	Unaffected: 1784795076 , < * (rpm) cpe:/a:redhat:rhui:5::el9
Red Hat	Red Hat Update Infrastructure 5	Unaffected: 1787241211 , < * (rpm) cpe:/a:redhat:rhui:5::el9
Red Hat	Red Hat Update Infrastructure 5	Unaffected: 1787241260 , < * (rpm) cpe:/a:redhat:rhui:5::el9
Red Hat	Red Hat Lightspeed proxy 1	cpe:/a:redhat:insights_proxy:1

Date Public

2026-05-22 14:00

Credits

"F5 acknowledges Mufeed VH of Winfunc Research, Nebula Security (@nebusecurity), and Vexera AI for bringing this issue to our attention and following the highest standards of coordinated disclosure."

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-9256",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-22T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-23T03:55:52.757Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-06-18T05:35:40.986Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/05/22/14"
          },
          {
            "url": "https://lists.debian.org/debian-lts-announce/2026/06/msg00023.html"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "affected": [
          {
            "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
            "cpes": [
              "cpe:/o:redhat:enterprise_linux:10.2"
            ],
            "defaultStatus": "affected",
            "packageName": "nginx",
            "product": "Red Hat Enterprise Linux 10",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "2:1.26.3-6.el10_2.4",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
            "cpes": [
              "cpe:/a:redhat:enterprise_linux:8"
            ],
            "defaultStatus": "affected",
            "packageName": "nginx:1.24",
            "product": "Red Hat Enterprise Linux 8",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "8100020260611094050.489197e6",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
            "cpes": [
              "cpe:/a:redhat:enterprise_linux:9"
            ],
            "defaultStatus": "affected",
            "packageName": "nginx:1.24",
            "product": "Red Hat Enterprise Linux 9",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "9080020260610161820.9",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
            "cpes": [
              "cpe:/a:redhat:enterprise_linux:9"
            ],
            "defaultStatus": "affected",
            "packageName": "nginx",
            "product": "Red Hat Enterprise Linux 9",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "2:1.20.1-28.el9_8.3",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
            "cpes": [
              "cpe:/a:redhat:enterprise_linux:9"
            ],
            "defaultStatus": "affected",
            "packageName": "nginx:1.26",
            "product": "Red Hat Enterprise Linux 9",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "9080020260609152155.9",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://catalog.redhat.com/software/containers/",
            "cpes": [
              "cpe:/a:redhat:discovery:2::el9"
            ],
            "defaultStatus": "affected",
            "packageName": "discovery/discovery-ui-rhel9",
            "product": "Red Hat Discovery 2",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "1782756541",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
            "cpes": [
              "cpe:/a:redhat:hummingbird:1"
            ],
            "defaultStatus": "affected",
            "packageName": "nginx-main",
            "product": "Red Hat Hardened Images",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "1.30.2-1.hum1",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://catalog.redhat.com/software/containers/",
            "cpes": [
              "cpe:/a:redhat:rhui:5::el9"
            ],
            "defaultStatus": "affected",
            "packageName": "rhui5/cds-kubernetes-rhel9",
            "product": "Red Hat Update Infrastructure 5",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "1784794818",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://catalog.redhat.com/software/containers/",
            "cpes": [
              "cpe:/a:redhat:rhui:5::el9"
            ],
            "defaultStatus": "affected",
            "packageName": "rhui5/cds-rhel9",
            "product": "Red Hat Update Infrastructure 5",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "1784794778",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://catalog.redhat.com/software/containers/",
            "cpes": [
              "cpe:/a:redhat:rhui:5::el9"
            ],
            "defaultStatus": "affected",
            "packageName": "rhui5/rhua-rhel9",
            "product": "Red Hat Update Infrastructure 5",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "1784795076",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://catalog.redhat.com/software/containers/",
            "cpes": [
              "cpe:/a:redhat:rhui:5::el9"
            ],
            "defaultStatus": "affected",
            "packageName": "rhui5/cds-kubernetes-tp-rhel9",
            "product": "Red Hat Update Infrastructure 5",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "1787241211",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://catalog.redhat.com/software/containers/",
            "cpes": [
              "cpe:/a:redhat:rhui:5::el9"
            ],
            "defaultStatus": "affected",
            "packageName": "rhui5/rhua-tp-rhel9",
            "product": "Red Hat Update Infrastructure 5",
            "vendor": "Red Hat",
            "versions": [
              {
                "lessThan": "*",
                "status": "unaffected",
                "version": "1787241260",
                "versionType": "rpm"
              }
            ]
          },
          {
            "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
            "cpes": [
              "cpe:/a:redhat:insights_proxy:1"
            ],
            "defaultStatus": "affected",
            "packageName": "insights-proxy/insights-proxy-container-rhel9",
            "product": "Red Hat Lightspeed proxy 1",
            "vendor": "Red Hat"
          }
        ],
        "datePublic": "2026-05-22T14:11:41.877Z",
        "descriptions": [
          {
            "lang": "en",
            "value": "A flaw was found in the ngx_http_rewrite_module module of NGINX. When a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures and a replacement string that references multiple such captures in a redirect or arguments context, an unauthenticated attacker can send crafted HTTP requests and cause a heap-based buffer overflow in the worker process, potentially allowing code execution or a denial of service by forcing the process to restart."
          }
        ],
        "metrics": [
          {
            "other": {
              "content": {
                "namespace": "https://access.redhat.com/security/updates/classification/",
                "value": "Important"
              },
              "type": "Red Hat severity rating"
            }
          },
          {
            "cvssV3_1": {
              "attackComplexity": "HIGH",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 8.1,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            },
            "format": "CVSS"
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-122",
                "description": "Heap-based Buffer Overflow",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-25T12:05:55.163Z",
          "orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
          "shortName": "redhat-SADP"
        },
        "references": [
          {
            "tags": [
              "vdb-entry",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/security/cve/CVE-2026-9256"
          },
          {
            "name": "RHBZ#2480746",
            "tags": [
              "issue-tracking",
              "x_refsource_REDHAT"
            ],
            "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2480746"
          },
          {
            "tags": [
              "x_sadp-csaf-vex"
            ],
            "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9256.json"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:29874"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:28921"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:28212"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:28973"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:29151"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:33313"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:20351"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:44481"
          },
          {
            "tags": [
              "vendor-advisory",
              "x_refsource_REDHAT"
            ],
            "url": "https://access.redhat.com/errata/RHSA-2026:58981"
          }
        ],
        "solutions": [
          {
            "lang": "en",
            "value": "RHSA-2026:29874: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:28921: Red Hat Enterprise Linux AppStream (v. 8)"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:28212: Red Hat Enterprise Linux AppStream (v. 9)"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:28973: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:29151: Red Hat Enterprise Linux AppStream (v. 9)"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:33313: Red Hat Discovery 2"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:20351: Red Hat Hardened Images"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:44481: Red Hat Update Infrastructure 5"
          },
          {
            "lang": "en",
            "value": "RHSA-2026:58981: Red Hat Update Infrastructure 5"
          }
        ],
        "timeline": [
          {
            "lang": "en",
            "time": "2026-05-22T15:00:55.131Z",
            "value": "Reported to Red Hat."
          },
          {
            "lang": "en",
            "time": "2026-05-22T14:11:41.877Z",
            "value": "Made public."
          }
        ],
        "title": "nginx: ngx_http_rewrite_module: code execution and denial of service",
        "workarounds": [
          {
            "lang": "en",
            "value": "To mitigate this vulnerability, use named captures instead of unnamed captures in rewrite definitions.\n\nFor example, the following rewrite directive uses unnamed PCRE capture groups, $1 and $2:\n\n~~~\nrewrite ^/users/([0-9]+)/profile/(.*)$ /profile.php?id=$1\u0026tab=$2 last;\n~~~\n\nTo mitigate this vulnerability for this example, replace $1 and $2 with the appropriate named captures, $user_id and $section:\n\n~~~\nrewrite ^/users/(?\u003cuser_id\u003e[0-9]+)/profile/(?\u003csection\u003e.*)$ /profile.php?id=$user_id\u0026tab=$section last;\n~~~"
          }
        ],
        "x_adpType": "supplier",
        "x_generator": {
          "engine": "sadp-cli 1.0.0"
        }
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "ngx_http_rewrite_module"
          ],
          "product": "NGINX Plus",
          "vendor": "F5",
          "versions": [
            {
              "lessThan": "37.0.1.1",
              "status": "affected",
              "version": "37.0",
              "versionType": "custom"
            },
            {
              "lessThan": "R36 P5",
              "status": "affected",
              "version": "R36",
              "versionType": "custom"
            },
            {
              "lessThan": "R32 P7",
              "status": "affected",
              "version": "R32",
              "versionType": "custom"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "modules": [
            "ngx_http_rewrite_module"
          ],
          "product": "NGINX Open Source",
          "vendor": "F5",
          "versions": [
            {
              "lessThan": "1.31.1",
              "status": "affected",
              "version": "1.31.0",
              "versionType": "custom"
            },
            {
              "lessThan": "1.30.2",
              "status": "affected",
              "version": "1.30.0",
              "versionType": "custom"
            },
            {
              "lessThanOrEqual": "0.9.7",
              "status": "affected",
              "version": "0.1.17",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "\"F5 acknowledges Mufeed VH of Winfunc Research, Nebula Security (@nebusecurity), and Vexera AI for bringing this issue to our attention and following the highest standards of coordinated disclosure.\""
        }
      ],
      "datePublic": "2026-05-22T14:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated."
            }
          ],
          "value": "NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        },
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 9.2,
            "baseSeverity": "CRITICAL",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-122",
              "description": "CWE-122 Heap-based Buffer Overflow",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-28T18:20:47.449Z",
        "orgId": "9dacffd4-cb11-413f-8451-fbbfd4ddc0ab",
        "shortName": "f5"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://my.f5.com/manage/s/article/K000161377"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "tags": [
        "x_F5"
      ],
      "title": "NGINX ngx_http_rewrite_module vulnerability",
      "x_generator": {
        "engine": "F5 SIRTBot v1.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9dacffd4-cb11-413f-8451-fbbfd4ddc0ab",
    "assignerShortName": "f5",
    "cveId": "CVE-2026-9256",
    "datePublished": "2026-05-22T14:11:41.877Z",
    "dateReserved": "2026-05-21T20:58:58.484Z",
    "dateUpdated": "2026-08-25T12:05:55.163Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

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

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.

Action not permitted

OESA-2026-2587 (CVE-2026-9256)

CVE-2026-9256 (GCVE-0-2026-9256)

Tags

Sightings

Nomenclature

Related by attack behaviour