Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2026-06-01 11:47

Modified

2026-06-01 12:05

Summary

NGINX ngx_http_rewrite_module vulnerability

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.

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

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "nginx",
        "purl": "pkg:bitnami/nginx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.1.17"
            },
            {
              "fixed": "1.24.0"
            },
            {
              "introduced": "1.30.0"
            },
            {
              "fixed": "1.30.2"
            },
            {
              "introduced": "1.31.0"
            },
            {
              "fixed": "1.31.1"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "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"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-9256"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:*"
    ],
    "severity": "Critical"
  },
  "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": "BIT-nginx-2026-9256",
  "modified": "2026-06-01T12:05:25.064Z",
  "published": "2026-06-01T11:47:00.396Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/05/22/14"
    },
    {
      "type": "WEB",
      "url": "https://my.f5.com/manage/s/article/K000161377"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9256"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "NGINX ngx_http_rewrite_module vulnerability"
}

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

Vulnerability from cvelistv5 – Published: 2026-05-22 14:11 – Updated: 2026-05-28 18:20 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 (v2.0.3)

CWE

CWE-122 - Heap-based Buffer Overflow

Assigner

References

2 references

URL	Tags
https://my.f5.com/manage/s/article/K000161377	vendor-advisory
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

2 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)

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

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        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-9256",
                "options": [
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                  },
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                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-22T00:00:00+00:00",
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        {
          "defaultStatus": "unknown",
          "modules": [
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          ],
          "product": "NGINX Plus",
          "vendor": "F5",
          "versions": [
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            },
            {
              "lessThan": "R36 P5",
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              "version": "R36",
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            },
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              "lessThan": "R32 P7",
              "status": "affected",
              "version": "R32",
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        },
        {
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            "ngx_http_rewrite_module"
          ],
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          "versions": [
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        }
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            "providerUrgency": "NOT_DEFINED",
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            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
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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.

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Vulnerability from bitnami_vulndb

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

Tags

Sightings

Nomenclature