CVE-2026-47070: HTTP/3 redirect handler leaks Authorization and Cookie headers to cross-origin redirect target in hackney

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-25 · updated 2026-07-24
Weakness: CWE-601

Description

Sensitive Data Exposure vulnerability in benoitc hackney allows Retrieve Embedded Sensitive Data. The HTTP/3 redirect handler in src/hackney_h3.erl passes the original request headers unchanged to the redirect target without performing any cross-origin check. When a client issues an HTTP/3 request with follow_redirect enabled and includes Authorization or Cookie headers, a server responding with a 3xx redirect to a different host will cause the client to forward those credentials verbatim to the new origin. The main hackney.erl module has maybe_strip_auth_on_redirect/2 (guarded by the location_trusted option) to address CVE-2018-1000007, but hackney_h3.erl is missing this protection entirely. This issue affects hackney: from 3.1.1 before 4.0.1.

Affected products

benoitc hackney: from 3.1.1 before 4.0.1 — fixed in 4.0.1

How to fix

Upgrade to a fixed version: benoitc hackney 4.0.1. Check the vendor advisory for mitigations.

References

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