CVE-2026-82438

HIGH
Published Sep 14, 2026 Modified Sep 14, 2026 CWE-346 CWE-942

Description

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.

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CVSS v3.1 Score

8.1
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0020
Probability of exploitation
0.10%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-346 CWE-346
CWE-942 CWE-942

References

Frequently Asked Questions

What is CVE-2026-82438? +
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. It has a CVSS v3.1 base score of 8.1 (HIGH).
How severe is CVE-2026-82438? +
CVE-2026-82438 has a CVSS v3.1 score of 8.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0020, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-82438? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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