Vulnerability-Lookup

ubuntu-cve-2026-78689

Vulnerability from osv_ubuntu

Published

2026-09-03 00:00

Modified

2026-09-03 00:00

Summary

Details

Description NGINX JavaScript (njs) has a vulnerability in the XML module's namespace prefix list parser, reachable through the xml.exclusiveC14n() method. An unauthenticated remote attacker can trigger it when an affected NGINX configuration passes an externally controlled XML namespace prefix list to that method. Both the njs and the QuickJS (qjs) engines are affected. A crafted prefix list causes an out-of-bounds write past the end of a heap allocation. With the njs engine, which is the engine used when the js_engine directive is absent, this corrupts adjacent objects and crashes the NGINX worker. With the QuickJS engine, the same call additionally leaks the prefix list on every invocation, causing worker memory to grow across requests. The official nginxinc/nginx-saml reference implementation is affected during SAML signature verification. It reads InclusiveNamespaces/@PrefixList from an untrusted SAML message and passes it to xml.exclusiveC14n() before the signature has been verified, so a valid SAML signature is not required. A crafted SAML Response, Assertion, LogoutRequest, or LogoutResponse is sufficient. Code execution has not been demonstrated and cannot be ruled out for all platforms, as the effect of the out-of-bounds write depends on conditions beyond the attacker's control. Impact This vulnerability allows remote attackers to cause a denial of service on the NGINX system, either through repeatable worker restarts or through worker memory growth or possibly trigger 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:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-78689	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-78689	REPORT
	https://my.f5.com/manage/s/article/K000162602	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnginx-mod-http-js",
            "binary_version": "0.8.2-1ubuntu1"
          },
          {
            "binary_name": "libnginx-mod-stream-js",
            "binary_version": "0.8.2-1ubuntu1"
          },
          {
            "binary_name": "njs",
            "binary_version": "0.8.2-1ubuntu1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libnginx-mod-js",
        "purl": "pkg:deb/ubuntu/libnginx-mod-js@0.8.2-1ubuntu1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.7.12-2",
        "0.8.2-1ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnginx-mod-http-js",
            "binary_version": "0.9.4-1ubuntu0.1~esm1"
          },
          {
            "binary_name": "libnginx-mod-stream-js",
            "binary_version": "0.9.4-1ubuntu0.1~esm1"
          },
          {
            "binary_name": "njs",
            "binary_version": "0.9.4-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:26.04:LTS",
        "name": "libnginx-mod-js",
        "purl": "pkg:deb/ubuntu/libnginx-mod-js@0.9.4-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.1-1ubuntu2",
        "0.9.1-1ubuntu3",
        "0.9.4-1~build1",
        "0.9.4-1",
        "0.9.4-1build1",
        "0.9.4-1build2",
        "0.9.4-1ubuntu0.1~esm1"
      ]
    }
  ],
  "aliases": [],
  "details": "Description NGINX JavaScript (njs) has a vulnerability in the XML module\u0027s namespace prefix list parser, reachable through the xml.exclusiveC14n() method. An unauthenticated remote attacker can trigger it when an affected NGINX configuration passes an externally controlled XML namespace prefix list to that method. Both the njs and the QuickJS (qjs) engines are affected. A crafted prefix list causes an out-of-bounds write past the end of a heap allocation. With the njs engine, which is the engine used when the js_engine directive is absent, this corrupts adjacent objects and crashes the NGINX worker. With the QuickJS engine, the same call additionally leaks the prefix list on every invocation, causing worker memory to grow across requests. The official nginxinc/nginx-saml reference implementation is affected during SAML signature verification. It reads InclusiveNamespaces/@PrefixList from an untrusted SAML message and passes it to xml.exclusiveC14n() before the signature has been verified, so a valid SAML signature is not required. A crafted SAML Response, Assertion, LogoutRequest, or LogoutResponse is sufficient. Code execution has not been demonstrated and cannot be ruled out for all platforms, as the effect of the out-of-bounds write depends on conditions beyond the attacker\u0027s control.  Impact This vulnerability allows remote attackers to cause a denial of service on the NGINX system, either through repeatable worker restarts or through worker memory growth or possibly trigger 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.",
  "id": "UBUNTU-CVE-2026-78689",
  "modified": "2026-09-03T00:00:00Z",
  "published": "2026-09-03T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-78689"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-78689"
    },
    {
      "type": "REPORT",
      "url": "https://my.f5.com/manage/s/article/K000162602"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-78689"
  ]
}

CVE-2026-78689 (GCVE-0-2026-78689)

Vulnerability from cvelistv5 – Published: 2026-09-02 15:40 – Updated: 2026-09-03 03:56

Title

NGINX ngx_http_js_module vulnerablility

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:L/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 2026-09-02 00:00 UTC

CWE

CWE-122

Assigner

f5 mitre root

References

1 reference

URL	Tags
https://my.f5.com/manage/s/article/K000162602	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
F5	NGINX JavaScript	Affected: 0.7.10 , < 1.0.1 (custom)

Date Public

2023-01-01 00:00

Credits

F5 acknowledges Vladimir Tokarev of Cyera and Sujal Tuladhar (EvilGenius) 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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                  },
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                  }
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                "role": "CISA Coordinator",
                "timestamp": "2026-09-02T00:00:00+00:00",
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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.

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.