CVE-2026-82431

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-14. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 5 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
59(Track)
EG Risk 59/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
40%
KEV
Not listed

Published

September 14, 2026

Last Modified

September 14, 2026

Advisory Details (2)

Auto-updated Sep 14, 2026
No patch confirmed yet.
generic

oss-security - CVE-2026-82431: Apache Storm Client: Authorization Bypass When nimbus.groups Is Configured Without nimbus.users

http://www.openwall.com/lists/oss-security/2026/09/13/11
generic
https://lists.apache.org/thread/s335qxb6woqb35ho3fpq7toytsz1gpts

Vendor Advisories for CVE-2026-82431(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 49× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-20 05:40 UTCGHSA enrichment
  2. 2026-09-20 01:33 UTCGHSA enrichment
  3. 2026-09-19 21:26 UTCGHSA enrichment
  4. 2026-09-19 17:19 UTCEG score recompute
  5. 2026-09-19 17:19 UTCGHSA enrichment
  6. 2026-09-19 13:12 UTCGHSA enrichment
  7. 2026-09-19 09:05 UTCGHSA enrichment
  8. 2026-09-19 04:58 UTCGHSA enrichment
  9. 2026-09-19 00:51 UTCGHSA enrichment
  10. 2026-09-18 20:45 UTCEG score recompute
  11. 2026-09-18 20:45 UTCGHSA enrichment
  12. 2026-09-18 19:28 UTCEPSS rescore
  13. 2026-09-18 16:21 UTCGHSA enrichment
  14. 2026-09-18 12:14 UTCGHSA enrichment
  15. 2026-09-18 08:05 UTCGHSA enrichment
  16. 2026-09-18 03:58 UTCGHSA enrichment
  17. 2026-09-17 23:51 UTCGHSA enrichment
  18. 2026-09-17 19:43 UTCEG score recompute
  19. 2026-09-17 19:43 UTCGHSA enrichment
  20. 2026-09-17 15:36 UTCGHSA enrichment
  21. 2026-09-17 11:28 UTCGHSA enrichment
  22. 2026-09-17 07:21 UTCGHSA enrichment
  23. 2026-09-17 03:13 UTCGHSA enrichment
  24. 2026-09-16 23:06 UTCGHSA enrichment
  25. 2026-09-16 18:59 UTCGHSA enrichment
Show 24 more
  1. 2026-09-16 14:52 UTCEG score recompute
  2. 2026-09-16 14:52 UTCGHSA enrichment
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 10:43 UTCGHSA enrichment
  5. 2026-09-16 06:36 UTCEG score recompute
  6. 2026-09-16 06:36 UTCGHSA enrichment
  7. 2026-09-16 05:15 UTCEPSS rescore
  8. 2026-09-16 02:30 UTCGHSA enrichment
  9. 2026-09-15 22:23 UTCGHSA enrichment
  10. 2026-09-15 18:14 UTCGHSA enrichment
  11. 2026-09-15 13:36 UTCGHSA enrichment
  12. 2026-09-15 09:29 UTCGHSA enrichment
  13. 2026-09-15 05:21 UTCGHSA enrichment
  14. 2026-09-15 01:10 UTCEG score recompute
  15. 2026-09-15 01:10 UTCGHSA enrichment
  16. 2026-09-14 21:03 UTCGHSA enrichment
  17. 2026-09-14 20:24 UTCGHSA enrichment
  18. 2026-09-14 20:15 UTCEG score recompute▲ 9.80
  19. 2026-09-14 20:15 UTCGHSA enrichment
  20. 2026-09-14 20:14 UTCMITRE cvelistV5CVSS v3 → 9.8 · severity → CRITICAL
  21. 2026-09-14 16:24 UTCGHSA enrichment
  22. 2026-09-14 15:21 UTCNVD update
  23. 2026-09-14 14:25 UTCEG score recompute
  24. 2026-09-14 14:24 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-82431?
CVE-2026-82431 is a critical vulnerability published on September 14, 2026. 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…
When was CVE-2026-82431 disclosed?
CVE-2026-82431 was first published in the National Vulnerability Database on September 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-82431 actively exploited?
CVE-2026-82431 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 59.7% of all scored CVEs.
What is the CVSS score of CVE-2026-82431?
CVE-2026-82431 has a CVSS v3.1 base score of 9.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-82431?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-82431, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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