CVE-2026-82431: Apache Storm Client · Incorrect Authorization
Affects Apache Storm ClientSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical : upgrade to 3.1.0 as a priority.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.1.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 14 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade Apache to 3.1.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Apache Software FoundationApache Storm Client | Affected
| Fixed in
|
MavenApache Software Foundation/org.apache.storm:storm-clientpkg:maven/Apache Software Foundation/org.apache.storm:storm-clientOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade to Apache Storm version 3.1.0 or later, where the authorization logic correctly evaluates nimbus.groups regardless of nimbus.users. For users unable to upgrade immediately, populate the nimbus.users list with intended principals to ensure group restrictions are enforced. Additionally, review Nimbus access logs for any operations performed by principals outside the intended groups to detect potential unauthorized access. After upgrading, be aware that clusters configured with only nimbus.groups will enforce restrictions for the first time, potentially denying access to clients outside those groups.
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.