Vulnerability · Published May 25, 2026 · Assigned by EEF
CVE-2026-47070HTTP/3 redirect handler leaks Authorization and Cookie headers to cross-origin redirect target in hackney
Medium 6.0
In plain English
A medium-severity open redirect in hackney from benoitc. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).
Official 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 (as reported)
Weakness: CWE-601 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N