Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-82431 is a critical-severity Incorrect Authorization (CWE-863) vulnerability in Apache Storm (inferred from references). Its CVSS base score is 9.8 (Critical).
Operationally, ranked at the 31th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-77525
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
AC-24 ensures access-control decisions are made and applied consistently, reducing the chance of an incorrect authorization result.
A reference monitor that is always invoked and tamper-proof forces every authorization decision through a verified, correct path.
AC-3 directly requires correct enforcement of authorization decisions on every access request, structurally preventing incorrect checks.
Least-privilege assignments shrink the set of authorizations that must be checked correctly, limiting exposure to flawed checks.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.
A.5.18's provisioning, revocation, review and adjustment of access rights (incl. before role changes/termination, with segregation and owner approval) directly stops incorrect authorization decisions from being exploitable in the vast majority of cases; the bounded remainder is incorrectness inside the authorization logic itself (e.g. flawed conditional or missing check) rather than rights that were wrongly granted.
A.8.3 directly mandates restricting access to information per policies via configuration, identity/group controls, isolation, and dynamic techniques that enforce correct authorization decisions, addressing most but not all slices of CWE-863 (e.g., remainder in non-access-decision authorization errors like timing or environmental factors).
Hardening callouts derived
DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.
- No fine-grained STIG row for CWE-863, a class-level weakness, and none of its children carries one either.