cvedb.io
CVE-2026-43974
UNKNOWN · CVSS n/a
EPSS exploitation probability: 0%
Published 2026-06-08T15:16:46.870 · Last modified 2026-06-17T10:50:09.073

Summary

Unexpected Status Code or Return Value vulnerability in ninenines gun (gun_http module) allows a malicious HTTP server to force the client into raw protocol mode via an unsolicited 101 Switching Protocols response. In gun_http:handle_inform/8, when a 101 Switching Protocols response is received over HTTP/1.1, the function verifies only that the Upgrade header is syntactically valid and that the stream reference is a plain reference(). It does not check whether the client ever sent an Upgrade or Connection: upgrade header on the corresponding request. Because this check is absent, any 101 response (solicited or not) causes gun to dispatch a gun_upgrade message to the caller and transition the entire connection to raw protocol mode. A malicious or compromised HTTP server can send an unsoli

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.