CVE-2026-89186 (GCVE-0-2026-89186)
Vulnerability from cvelistv5
Published
2026-09-16 08:24
Modified
2026-09-16 14:50
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-524 - Use of Cache Containing Sensitive Information
Summary
Use of Cache Containing Sensitive Information in ZenHive mpp allows a shared HTTP cache to store a paid response and serve it to clients that never paid.
MPP.Plug.verify_credential in lib/mpp/plug.ex sets payment-receipt and cache-control: private on the connection before the wrapped application runs, and registers no register_before_send/2 callback. Plug.Conn.put_resp_header/3 replaces an existing header, so a mounting application that sets its own cache-control on the paid resource (for example public, max-age=3600) silently overrides the private the library relies on, and a CDN or reverse proxy can then store the paid 200 together with its Payment-Receipt and serve both to unpaid clients. The library-level guarantee is therefore defeatable by the application it protects. For the same reason a downstream non-2xx response still carried Payment-Receipt, issuing a receipt for a response that delivered no resource.
This issue affects mpp: from 0.1.0 before 0.16.2.
References
Impacted products
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For the same reason a downstream non-2xx response still carried Payment-Receipt, issuing a receipt for a response that delivered no resource.\\n\\nThis issue affects mpp: from 0.1.0 before 0.16.2.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003eUse of Cache Containing Sensitive Information in ZenHive mpp allows a shared HTTP cache to store a paid response and serve it to clients that never paid.\u003c/p\u003e\\n\u003cp\u003e\u003ccode\u003eMPP.Plug.verify_credential\u003c/code\u003e in \u003ccode\u003elib/mpp/plug.ex\u003c/code\u003e sets \u003ccode\u003epayment-receipt\u003c/code\u003e and \u003ccode\u003ecache-control: private\u003c/code\u003e on the connection before the wrapped application runs, and registers no \u003ccode\u003eregister_before_send/2\u003c/code\u003e callback. \u003ccode\u003ePlug.Conn.put_resp_header/3\u003c/code\u003e replaces an existing header, so a mounting application that sets its own \u003ccode\u003ecache-control\u003c/code\u003e on the paid resource (for example \u003ccode\u003epublic, max-age=3600\u003c/code\u003e) silently overrides the \u003ccode\u003eprivate\u003c/code\u003e the library relies on, and a CDN or reverse proxy can then store the paid 200 together with its \u003ccode\u003ePayment-Receipt\u003c/code\u003e and serve both to unpaid clients. The library-level guarantee is therefore defeatable by the application it protects. For the same reason a downstream non-2xx response still carried \u003ccode\u003ePayment-Receipt\u003c/code\u003e, issuing a receipt for a response that delivered no resource.\u003c/p\u003e\\n\u003cp\u003eThis issue affects mpp: from 0.1.0 before 0.16.2.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"Use of Cache Containing Sensitive Information in ZenHive mpp allows a shared HTTP cache to store a paid response and serve it to clients that never paid.\\n\\n`MPP.Plug.verify_credential` in `lib/mpp/plug.ex` sets `payment-receipt` and `cache-control: private` on the connection before the wrapped application runs, and registers no `register_before_send/2` callback. `Plug.Conn.put_resp_header/3` replaces an existing header, so a mounting application that sets its own `cache-control` on the paid resource (for example `public, max-age=3600`) silently overrides the `private` the library relies on, and a CDN or reverse proxy can then store the paid 200 together with its `Payment-Receipt` and serve both to unpaid clients. The library-level guarantee is therefore defeatable by the application it protects. For the same reason a downstream non-2xx response still carried `Payment-Receipt`, issuing a receipt for a response that delivered no resource.\\n\\nThis issue affects mpp: from 0.1.0 before 0.16.2.\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-524\", \"description\": \"CWE-524 Use of Cache Containing Sensitive Information\"}]}], \"configurations\": [{\"lang\": \"en\", \"value\": \"Reachable only where the application mounted behind MPP.Plug sets its own Cache-Control on the paid resource, overriding the private the library wrote, and a shared HTTP cache (CDN or reverse proxy) sits in front of that route. An application that sets no Cache-Control of its own keeps the library\u0027s private and is not affected.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003eReachable only where the application mounted behind \u003ccode\u003eMPP.Plug\u003c/code\u003e sets its own \u003ccode\u003eCache-Control\u003c/code\u003e on the paid resource, overriding the \u003ccode\u003eprivate\u003c/code\u003e the library wrote, and a shared HTTP cache (CDN or reverse proxy) sits in front of that route. An application that sets no \u003ccode\u003eCache-Control\u003c/code\u003e of its own keeps the library\u0027s \u003ccode\u003eprivate\u003c/code\u003e and is not affected.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"Reachable only where the application mounted behind `MPP.Plug` sets its own `Cache-Control` on the paid resource, overriding the `private` the library wrote, and a shared HTTP cache (CDN or reverse proxy) sits in front of that route. An application that sets no `Cache-Control` of its own keeps the library\u0027s `private` and is not affected.\", \"base64\": false}]}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"0.16.2\", \"versionStartIncluding\": \"0.1.0\"}], \"operator\": \"OR\"}], \"operator\": \"AND\"}], \"providerMetadata\": {\"orgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"shortName\": \"EEF\", \"dateUpdated\": \"2026-09-16T08:24:15.058Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-89186\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-09-16T14:50:44.399Z\", \"dateReserved\": \"2026-09-11T19:00:02.549Z\", \"assignerOrgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"datePublished\": \"2026-09-16T08:24:15.058Z\", \"assignerShortName\": \"EEF\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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