Vulnerability-Lookup

ALSA-2026:67315

Vulnerability from osv_almalinux

Published

2026-09-14 00:00

Modified

2026-09-15 08:37

Summary

Moderate: nginx:1.24 security update

Details

nginx is a web and proxy server supporting HTTP and other protocols, with a focus on high concurrency, performance, and low memory usage.

Security Fix(es):

nginx: NGINX: Arbitrary code execution via crafted HTTP requests (CVE-2026-42533)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

References

URL

Type

	https://access.redhat.com/errata/RHSA-2026:67315	ADVISORY
	https://access.redhat.com/security/cve/CVE-2026-42533	REPORT
	https://bugzilla.redhat.com/2500967	REPORT
	https://errata.almalinux.org/8/ALSA-2026-67315.html	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "nginx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.24.0-3.module_el8.10.0+4275+5756017d.5.alma.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "nginx-all-modules"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.24.0-3.module_el8.10.0+4275+5756017d.5.alma.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "nginx-filesystem"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.24.0-3.module_el8.10.0+4275+5756017d.5.alma.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "nginx-mod-devel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.24.0-3.module_el8.10.0+4275+5756017d.5.alma.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "nginx-mod-http-image-filter"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.24.0-3.module_el8.10.0+4275+5756017d.5.alma.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "nginx-mod-http-perl"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.24.0-3.module_el8.10.0+4275+5756017d.5.alma.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "nginx-mod-http-xslt-filter"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.24.0-3.module_el8.10.0+4275+5756017d.5.alma.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "nginx-mod-mail"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.24.0-3.module_el8.10.0+4275+5756017d.5.alma.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "nginx-mod-stream"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.24.0-3.module_el8.10.0+4275+5756017d.5.alma.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "nginx is a web and proxy server supporting HTTP and other protocols, with a focus on high concurrency, performance, and low memory usage.   \n\nSecurity Fix(es):  \n\n  * nginx: NGINX: Arbitrary code execution via crafted HTTP requests (CVE-2026-42533)\n\n\nFor more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.\n",
  "id": "ALSA-2026:67315",
  "modified": "2026-09-15T08:37:27Z",
  "published": "2026-09-14T00:00:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:67315"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-42533"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2500967"
    },
    {
      "type": "ADVISORY",
      "url": "https://errata.almalinux.org/8/ALSA-2026-67315.html"
    }
  ],
  "related": [
    "CVE-2026-42533"
  ],
  "summary": "Moderate: nginx:1.24 security update"
}

CVE-2026-42533 (GCVE-0-2026-42533)

Vulnerability from cvelistv5 – Published: 2026-07-15 14:33 – Updated: 2026-07-29 03:55

Title

NGINX Map directive and Regex matching vulnerability

Summary

A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. 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. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

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:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-15 00:00 UTC

CWE

CWE-122 - Heap-based Buffer Overflow

Assigner

f5 mitre root

References

1 reference

URL	Tags
https://my.f5.com/manage/s/article/K000162097	vendor-advisorypatch

Impacted products

2 products

Vendor	Product	Version
F5	NGINX Plus	Affected: 37.0.0.1 , < 37.0.3.1 (custom) Affected: R36 , < R36 P7 (custom) Affected: R33 , < * (custom)
F5	NGINX Open Source	Affected: 1.31.2 , < 1.31.3 (custom) Affected: 0.9.6 , < 1.30.4 (custom)

Date Public

2026-07-15 14:00

Credits

F5 acknowledges Ming Xuan, DKD (@pidifn), Ji'an Zhou, and Zhen Yan of AntAISecurityLab, Rafael Gacek, Sergii Negodiuk of EVO.company, Lam Jun Rong of Calif.io, Mufeed VH of Winfunc Research (winfunc.com), Vexera AI (https://vexera.ai), Tu Tran Dinh (@1w4y), Stan Shaw (cyberstan), qianshuidewajueji, zenneth (randomguy6407), Zhenpeng (Leo) Lin of depthfirst, Lukas Johannes Moeller, Melih Tolga Sahin of Vodafone Türkiye, Ayoub Nabil Boubagrat (GitHub: @ayoubnabil), and Milan Jovic (Kljunowsky) for independently 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-2026-42533",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-15T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-29T03:55:24.843Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "map directive with regex matching"
          ],
          "product": "NGINX Plus",
          "vendor": "F5",
          "versions": [
            {
              "lessThan": "37.0.3.1",
              "status": "affected",
              "version": "37.0.0.1",
              "versionType": "custom"
            },
            {
              "lessThan": "R36 P7",
              "status": "affected",
              "version": "R36",
              "versionType": "custom"
            },
            {
              "lessThan": "*",
              "status": "affected",
              "version": "R33",
              "versionType": "custom"
            }
          ]
        },
        {
          "defaultStatus": "unknown",
          "modules": [
            "map directive with regex matching"
          ],
          "product": "NGINX Open Source",
          "vendor": "F5",
          "versions": [
            {
              "lessThan": "1.31.3",
              "status": "affected",
              "version": "1.31.2",
              "versionType": "custom"
            },
            {
              "lessThan": "1.30.4",
              "status": "affected",
              "version": "0.9.6",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "F5 acknowledges Ming Xuan, DKD (@pidifn), Ji\u0027an Zhou, and Zhen Yan of AntAISecurityLab, Rafael Gacek, Sergii Negodiuk of EVO.company, Lam Jun Rong of Calif.io, Mufeed VH of Winfunc Research (winfunc.com), Vexera AI (https://vexera.ai), Tu Tran Dinh (@1w4y), Stan Shaw (cyberstan), qianshuidewajueji, zenneth (randomguy6407), Zhenpeng (Leo) Lin of depthfirst, Lukas Johannes Moeller, Melih Tolga Sahin of Vodafone T\u00fcrkiye, Ayoub Nabil Boubagrat (GitHub: @ayoubnabil), and Milan Jovic (Kljunowsky) for independently bringing this issue to our attention and following the highest standards of coordinated disclosure."
        }
      ],
      "datePublic": "2026-07-15T14:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eA vulnerability exists in NGINX Plus and NGINX Open Source when a \u003cstrong\u003emap\u003c/strong\u003e\u0026nbsp;directive uses regex matching and a string expression references the map\u0027s regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. 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.\u003c/p\u003eImpact:\u003cbr\u003eThis vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only.\u003cbr\u003e\n\n\n\u003cbr\u003e\u0026nbsp;Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated."
            }
          ],
          "value": "A vulnerability exists in NGINX Plus and NGINX Open Source when a map\u00a0directive uses regex matching and a string expression references the map\u0027s regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. 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\nImpact:\nThis vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only.\n\n\n\n\n\u00a0Note: 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": "NONE",
            "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:N/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": "2026-07-15T21:20:26.156Z",
        "orgId": "9dacffd4-cb11-413f-8451-fbbfd4ddc0ab",
        "shortName": "f5"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory",
            "patch"
          ],
          "url": "https://my.f5.com/manage/s/article/K000162097"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "NGINX Map directive and Regex matching vulnerability",
      "x_generator": {
        "engine": "F5 SIRTBot v1.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9dacffd4-cb11-413f-8451-fbbfd4ddc0ab",
    "assignerShortName": "f5",
    "cveId": "CVE-2026-42533",
    "datePublished": "2026-07-15T14:33:45.810Z",
    "dateReserved": "2026-05-05T21:19:09.517Z",
    "dateUpdated": "2026-07-29T03:55:24.843Z",
    "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.

Detection rules are retrieved from Rulezet.

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.