CVE-2026-47070 HTTP/3 redirect handler leaks Authorization and Cookie headers to cross-origin redirect target in hackney
Hackney HTTP/3 client leaks Authorization and Cookie headers to cross-origin redirect targets, exposing sensitive credentials to attackers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-47070?
CVE-2026-47070 is a medium-severity vulnerability in benoitc hackney, published on 25 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
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.
Weakness: CWE-601
Which versions are affected by CVE-2026-47070?
3 open source packages ship an affected version, including hackney. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
hackney Hex | From 3.1.1 | 4.0.1 |
hackney Hex | From 3.1.1 | 4.0.1 |
hackney Hex | From 3.1.1 | 4.0.1 |
Products include Benoitc Hackney.
How do I fix CVE-2026-47070?
Upgrade hackney to 4.0.1 or later.
Is CVE-2026-47070 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-47070 exists.
Other vulnerabilities in benoitc hackney
- CVE-2026-47066 Infinite loop in Alt-Svc header parser in hackney
- CVE-2026-47067 Atom table exhaustion via unrecognized URL schemes in hackney
- CVE-2026-47073 Unbounded memory consumption in WebSocket client in hackney
- CVE-2026-47071 SOCKS5 TLS upgrade ignores caller timeout in hackney
- CVE-2026-47077 Unbounded body accumulation in HTTP/3 response loop in hackney
Sources
Also known as EEF-CVE-2026-47070, GHSA-h73q-4w9q-82h4.