What is CVE-2026-82438?

CVE-2026-82438 is Apache Storm Webapp: Authenticated API Responses Exposed to Arbitrary Web Origins. The supplied enrichment data classifies it as Unclassified mapped to CWE-346 CWE-346; CWE-942 CWE-942.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-82438. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-82438 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

A public PoC is not confirmed from current sources for CVE-2026-82438. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with Not reported where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-82438 using CVSS null, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Prioritize based on EPSS, PoC availability, and external exposure. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CVE-2026-82438

CVE-2026-82438 — Apache Storm Webapp: Authenticated API Responses Exposed to Arbitrary Web Origins

Description Three separate mechanisms allowed a web page on an unrelated origin to read responses that Storm's HTTP components served to an authenticated user. The Logviewer reflected the request's `Origin` header back in `Access-Control-Allow-Origin` while also sending `Access-Control-Allow-Credentials: true`. The published security model documents a permissive `Access-Control-Allow-Origin: *` posture as accepted, which is safe precisely because browsers refuse to honour `*` together with credentials; reflecting the concrete origin removes that protection. The shared CORS filter used by the UI, the Logviewer and DRPC was configured with a response header name where an initialisation parameter name was expected. The container ignored the setting and applied its own defaults, which allow credentials. Finally, the UI and Logviewer wrapped API responses in a caller-supplied JSONP callback for every GET request. A script element on any origin can load such a response, which bypasses the same-origin policy entirely rather than negotiating it, and there was no way to turn the behaviour off. In each case the effect is that a page visited by an authenticated operator can read cluster, topology and log data on their behalf. Mitigation Upgrade to 3.1.0, where the Logviewer no longer reflects the request origin in a credentialed response, the CORS filter is configured explicitly, and JSONP wrapping is governed by `ui.enable.jsonp`, which defaults to false. Note that disabling JSONP is a behaviour change for tooling that passes a `callback` query parameter; such tooling should be moved to ordinary JSON requests. Users who cannot upgrade immediately should place the UI, Logviewer and DRPC HTTP endpoints behind a reverse proxy that strips `Access-Control-Allow-Origin` and `Access-Control-Allow-Credentials` from responses and rejects requests carrying a `callback` parameter. Credit The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.

Published Sep 14, 2026Updated Sep 14, 2026Sources: NVD, Apache Software Foundation (CNA), GitHub, GitHub Security Advisory, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

ahead of 0% of scored CVEs

Affects

Apache

Apache Storm Webapp

CVSS base

Unscored

no source published a base score

Remediation

The vendor's own words where we have them.

Upgrade Apache Storm Webapp to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Prioritize based on EPSS, PoC availability, and external exposure.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
Apache	Apache Storm Webapp	3.0.0 to < 3.1.0	Vulnerable

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-942 · Permissive Cross-domain Policy with Untrusted Domains

Execute Unauthorized Code or Commands
Bypass Protection Mechanism
Read Application Data
Varies by Context

Mitigation: Avoid using wildcards in the cross-domain policy file. Any domain matching the wildcard expression will be implicitly trusted, and can perform two-way interaction with the target server.

CWE-346 · Origin Validation Error

Gain Privileges or Assume Identity
Varies by Context

Weakness & attack patterns

CWE-346
CWE-942

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-75 · Manipulating Writeable Configuration FilesCAPEC-89 · PharmingCAPEC-387 · Navigation Remapping To Propagate Malicious ContentCAPEC-142 · DNS Cache PoisoningCAPEC-388 · Application API Button HijackingCAPEC-510 · SaaS User Request ForgeryCAPEC-384 · Application API Message Manipulation via Man-in-the-MiddleCAPEC-141 · Cache PoisoningCAPEC-111 · JSON Hijacking (aka JavaScript Hijacking)CAPEC-21 · Exploitation of Trusted IdentifiersCAPEC-160 · Exploit Script-Based APIsCAPEC-59 · Session Credential Falsification through Prediction

T1557.002Adversary-in-the-Middle: ARP Cache Poisoning
T1584.002Compromise Infrastructure: DNS Server
T1134Access Token Manipulation

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Initial · CVE published
Sep 14, 2026 · NVD
Added · GHSA-xf44-6rjp-v8cm published (unknown)
Sep 14, 2026 · GitHub Security Advisory
CVE published by MITRE.
Sep 14, 2026 · SOCRadar CTI

References

4 on the record

lists.apache.org/thread/2o7tl3hcdd865njxsn4d9cxp1frkctz3
Vendor Advisory
www.openwall.com/lists/oss-security/2026/09/13/17
Vendor Advisory
nvd.nist.gov/vuln/detail/CVE-2026-82438
NVD
github.com/advisories/GHSA-xf44-6rjp-v8cm
Exploit, Third Party Advisory

Coverage

2 stories from the feeds we poll

Elsewhere on this site

Apacheevery CVE for this vendor
Unclassifiedsame class
CWE-346other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-82438 is Apache Storm Webapp: Authenticated API Responses Exposed to Arbitrary Web Origins, a unscored vulnerability affecting Apache Storm Webapp from Apache Software Foundation. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-82438. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-82438. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS null describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.