{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": [
              "cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*",
              "cpe:2.3:a:f5:nginx_open_source:1.31.0:*:*:*:*:*:*:*"
            ],
            "extracted_events": [
              {
                "introduced": "0.1.17"
              },
              {
                "last_affected": "0.9.7"
              },
              {
                "introduced": "1.0.0"
              },
              {
                "last_affected": "1.30.1"
              },
              {
                "introduced": "1.31.0"
              },
              {
                "last_affected": "1.31.0"
              }
            ],
            "source": [
              "CPE_RANGE",
              "CPE_STRING"
            ]
          },
          "events": [
            {
              "introduced": "805d9db723e74bbe84e6df1be29fda28abcc23ea"
            },
            {
              "last_affected": "955370fc8c12b1a945941f844adc9df49a0f3f32"
            },
            {
              "introduced": "a2a09a84eb0a7059880500e70b40796ab1dd0c4d"
            },
            {
              "last_affected": "9a503b1317c283e1fd0f27008428ea441c1ac9ee"
            },
            {
              "introduced": "e8053c867f9ab14f323e3019ccab585d857abb66"
            },
            {
              "last_affected": "e8053c867f9ab14f323e3019ccab585d857abb66"
            }
          ],
          "repo": "https://github.com/nginx/nginx",
          "type": "GIT"
        }
      ],
      "versions": [
        "1.31.0"
      ]
    }
  ],
  "database_specific": {
    "unresolved_ranges": [
      {
        "cpes": [
          "cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*"
        ],
        "extracted_events": [
          {
            "introduced": "37.0.0"
          },
          {
            "fixed": "37.0.1.1"
          },
          {
            "introduced": "r32"
          },
          {
            "last_affected": "r36"
          }
        ],
        "source": "CPE_RANGE",
        "vendor_product": "f5:nginx_plus"
      }
    ]
  },
  "details": "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.",
  "id": "CVE-2026-9256",
  "modified": "2026-07-08T05:36:51.573136202Z",
  "published": "2026-05-22T15:16:27.073Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-9256"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2026/06/msg00023.html"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9256.json"
    },
    {
      "type": "ADVISORY",
      "url": "http://www.openwall.com/lists/oss-security/2026/05/22/14"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:20351"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:28212"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:28921"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:28973"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:29151"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:29874"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33313"
    },
    {
      "type": "ADVISORY",
      "url": "https://my.f5.com/manage/s/article/K000161377"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2480746"
    }
  ],
  "severity": [
    {
      "score": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}