`CVE-2026-82431`

Severity	9.8 Critical CVSS 3.1
Weakness	Incorrect authorization (CWE-863)
Published	14 Sep 2026

Published 2 months ago. NVD often adds the list of affected products days or weeks after a CVE is published, and the other sources we check lag too. The scope and status here may change.

Description

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.

Exploitation status

No public exploit

No exploit has been reported in the sources we check.

CISA KEV not listed
VulnCheck KEV not listed
CISA Vulnrichment exploitation: none
Indexed PoC none indexed
EPSS 0.39% chance in 30 days

Waratek protection

No exploit published

Within Waratek scope. In the sources we check, nobody has published exploit code for this CVE or reported it being exploited.

VRT has not found a public code change for this CVE yet.

Protection none
Action not pursued
Review automated Upstream data
Record active

Decided by	Nothing to build a rule from yet: no published exploit, no CISA record of exploitation and no source-level change to read
Finding	This CVE affects a known product, but nothing published names a fix and nothing published shows an exploit. That is a statement about the evidence, not about the defect — it does not mean the vulnerability is unimportant or unreachable, only that neither of the two things VRT can act on exists.

Decided by

Nothing to build a rule from yet: no published exploit, no CISA record of exploitation and no source-level change to read

Finding

This CVE affects a known product, but nothing published names a fix and nothing published shows an exploit. That is a statement about the evidence, not about the defect — it does not mean the vulnerability is unimportant or unreachable, only that neither of the two things VRT can act on exists.

References

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

URL

Timeline

Published	2026-09-14	By the CVE Program.
NVD record modified	2026-09-14	NVD's own last-modified date for this record.

Published

2026-09-14

By the CVE Program.

NVD record modified

2026-09-14

NVD's own last-modified date for this record.

How VRT decided (18 of 24 rules ran)

18 of 24 rules ran. The rest didn't run because an earlier rule had already settled the CVE.

# Rule Outcome Status Detail

identity: Does this identifier describe a vulnerability at all? the first rule that matches decides

1 rejected no match CVE Program withdrawal of this identifier

scope: Is it a vulnerability Waratek protects? the first rule that matches decides

2 armr-patch-file no match An ARMR patch file on disk for this CVE

3 armr-secure-rule-file no match An ARMR security-rule template on disk for this CVE

4 manual-classification no match A researcher's recorded decision for this specific CVE

5 manual classification no match Manual classification of this CVE in the legacy dataset

6 non-java-upstream no match A root cause in non-Java code: an OS kernel, a C library, or a bundled runtime

7 oracle-component no match The defect being in a component of a tracked product the agent does not reach: JavaFX, the Java SE installer, the JInitiator browser plug-in, the native WebLogic proxy plug-in, or a native part of Oracle Application Server or Collaboration Suite (HTTP Server, Web Cache, Internet Directory, mail and calendar servers). Oracle gives these no CPE of their own and names them only in the description.

8 java-client-side no match Oracle's own risk-matrix note saying the CVE is reached only through untrusted code in the Java sandbox (applets, Web Start) or only through a client installation of Java, so a server running its own trusted code is not exposed

9 osv-maven no match An OSV.dev record of this CVE affecting a package published to Maven Central. When every such package is one business applications do not use (Minecraft mods and launchers, Fastjson) and no tracked product is named by CPE, it settles the CVE as Outside Waratek scope instead

10 cna-maven-package matched In scope CNA declares the affected component is a Maven artifact

11 known-cpe-product not reached An NVD CPE naming a product ARMR tracks

12 cna-cpe-product not reached A CPE the CNA published naming a tracked product. Oracle publishes these on advisory day, months before NVD.

13 oracle-advisory-family not reached A tracked product family named in Oracle's own risk matrix. CPE cannot carry a suite name, only a module.

14 cna-named-product not reached A tracked product named in words by the CVE's own CNA, on a record with no CPE yet. Apache and Eclipse publish these on advisory day, before NVD adds CPE data.

15 non-deployable-product not reached The only affected product being a sealed appliance image, where Java runs but no -javaagent can be attached

16 unmatched-product not reached No tracked product matched above, and none present at all

disposition: What do we do about one that is? every rule runs

17 patch-hint no match A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug

18 open-source-maven no match The affected package being open source on Maven, so the fix can be read

19 poc-derivable no match An indexed exploit clearing the evidence bar to reverse-engineer, where there is no source to read

20 no-exploit decided it matched No exploit published No public exploits or POCs found in Exploit-DB, Nuclei templates, Metasploit modules, or GitHub POC repositories, and CISA's Vulnrichment assessment records no demonstrated exploit. No upstream fix reference or open-source Maven package was found either, so there is nothing to act on from either direction.

21 secure-rule-match no match A vulnerability class already blocked by an ARMR security rule

22 exploited-no-fix-or-poc skipped Somebody exploiting this CVE (a CISA or VulnCheck KEV listing, or a CISA verdict of active exploitation), with no fix, source code or PoC to build a rule from

23 below-action-threshold skipped Medium or Low severity, no CISA or VulnCheck KEV listing, no PoC clearing the evidence bar, no CISA verdict, no Oracle advisory

24 no-exploit-published skipped Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all

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