Vulnerability-Lookup

CVE-2026-82431 (GCVE-0-2026-82431)

Vulnerability from cvelistv5 – Published: 2026-09-14 14:14 – Updated: 2026-09-14 20:01

Title

Apache Storm Client: Authorization Bypass When nimbus.groups Is Configured Without nimbus.users

Summary

Description `SimpleACLAuthorizer` evaluated the user-level command set by returning early when `nimbus.users` was empty, before `nimbus.groups` was considered. An operator who restricted cluster access by group alone, leaving `nimbus.users` unset, therefore received no restriction at all: every authenticated principal was permitted every user-level operation, including `submitTopology`, `beginFileUpload` and `getNimbusConf`. `docs/SECURITY.md` presents `nimbus.groups` as a supported way to lock down a cluster, so a deployment following the documentation could believe it was restricted while it was not. The failure is silent; nothing in the logs or the configuration indicates that the group list is being ignored. Both lists left empty continues to mean that no restriction is configured, which is the shipped default and is unchanged. Mitigation Upgrade to 3.1.0, where `nimbus.groups` is evaluated whether or not `nimbus.users` is set. Users who cannot upgrade immediately should additionally populate `nimbus.users` with the intended principals, since a non-empty user list causes the group list to be evaluated on affected versions. Operators should review Nimbus access logs for operations by principals outside the intended groups. Note that after upgrading, a cluster configured with `nimbus.groups` alone becomes restrictive for the first time. This includes `NimbusClient`, which calls `getLeader` on every connection, so clients outside the configured groups will begin to be refused. Credit The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.

Severity

9.8 (Critical)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-14 20:01 UTC

CWE

CWE-863 - Incorrect Authorization

Assigner

apache mitre root

References

2 references

URL	Tags
https://lists.apache.org/thread/s335qxb6woqb35ho3…	vendor-advisory
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

1 product

Vendor	Product	Version	CPE status
Apache Software Foundation	Apache Storm Client	Affected: 3.0.0 , < 3.1.0 (semver)	guessed

Credits

The ASF using Claude Agents

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-82431

Vulnerability from fkie_nvd - Published: 2026-09-14 15:17 - Updated: 2026-09-14 20:58

Severity

9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

References

	URL	Tags
	security@apache.org	https://lists.apache.org/thread/s335qxb6woqb35ho3fpq7toytsz1gpts
	af854a3a-2127-422b-91ae-364da2661108	http://www.openwall.com/lists/oss-security/2026/09/13/11

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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    }
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  "lastModified": "2026-09-14T20:58:48.430",
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          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-14T20:01:33.385522Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-14T15:17:10.053",
  "references": [
    {
      "source": "security@apache.org",
      "url": "https://lists.apache.org/thread/s335qxb6woqb35ho3fpq7toytsz1gpts"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "http://www.openwall.com/lists/oss-security/2026/09/13/11"
    }
  ],
  "sourceIdentifier": "security@apache.org",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-863"
        }
      ],
      "source": "security@apache.org",
      "type": "Secondary"
    }
  ]
}

GHSA-45M3-3J6G-XV67

Vulnerability from github – Published: 2026-09-14 15:32 – Updated: 2026-09-14 21:31

Details

Description

SimpleACLAuthorizer evaluated the user-level command set by returning early when nimbus.users was empty, before nimbus.groups was considered. An operator who restricted cluster access by group alone, leaving nimbus.users unset, therefore received no restriction at all: every authenticated principal was permitted every user-level operation, including submitTopology, beginFileUpload and getNimbusConf.

docs/SECURITY.md presents nimbus.groups as a supported way to lock down a cluster, so a deployment following the documentation could believe it was restricted while it was not. The failure is silent; nothing in the logs or the configuration indicates that the group list is being ignored.

Both lists left empty continues to mean that no restriction is configured, which is the shipped default and is unchanged.

Mitigation

Upgrade to 3.1.0, where nimbus.groups is evaluated whether or not nimbus.users is set.

Users who cannot upgrade immediately should additionally populate nimbus.users with the intended principals, since a non-empty user list causes the group list to be evaluated on affected versions. Operators should review Nimbus access logs for operations by principals outside the intended groups.

Note that after upgrading, a cluster configured with nimbus.groups alone becomes restrictive for the first time. This includes NimbusClient, which calls getLeader on every connection, so clients outside the configured groups will begin to be refused.

Credit

The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.

Severity

9.8 (Critical)


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

Show details on source website

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{
  "affected": [],
  "aliases": [
    "CVE-2026-82431"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-863"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-14T15:17:10Z",
    "severity": "CRITICAL"
  },
  "details": "Description\n\n`SimpleACLAuthorizer` evaluated the user-level command set by returning early when `nimbus.users` was empty,\nbefore `nimbus.groups` was considered. An operator who restricted cluster access by group alone, leaving\n`nimbus.users` unset, therefore received no restriction at all: every authenticated principal was permitted\nevery user-level operation, including `submitTopology`, `beginFileUpload` and `getNimbusConf`.\n\n`docs/SECURITY.md` presents `nimbus.groups` as a supported way to lock down a cluster, so a deployment\nfollowing the documentation could believe it was restricted while it was not. The failure is silent; nothing\nin the logs or the configuration indicates that the group list is being ignored.\n\nBoth lists left empty continues to mean that no restriction is configured, which is the shipped default and\nis unchanged.\n\nMitigation\n\nUpgrade to 3.1.0, where `nimbus.groups` is evaluated whether or not `nimbus.users` is set.\n\nUsers who cannot upgrade immediately should additionally populate `nimbus.users` with the intended\nprincipals, since a non-empty user list causes the group list to be evaluated on affected versions.\nOperators should review Nimbus access logs for operations by principals outside the intended groups.\n\nNote that after upgrading, a cluster configured with `nimbus.groups` alone becomes restrictive for the first\ntime. This includes `NimbusClient`, which calls `getLeader` on every connection, so clients outside the\nconfigured groups will begin to be refused.\n\nCredit\n\nThe ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.",
  "id": "GHSA-45m3-3j6g-xv67",
  "modified": "2026-09-14T21:31:40Z",
  "published": "2026-09-14T15:32:49Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-82431"
    },
    {
      "type": "WEB",
      "url": "https://lists.apache.org/thread/s335qxb6woqb35ho3fpq7toytsz1gpts"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/09/13/11"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

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.

Action not permitted

CVE-2026-82431 (GCVE-0-2026-82431)

FKIE_CVE-2026-82431

GHSA-45M3-3J6G-XV67

Tags

Sightings

Nomenclature