CVE-2026-48856 httpc leaks Authorization header to cross-origin redirect targets
Attackers can steal Authorization headers via cross-origin redirects in Erlang OTP httpc, exposing sensitive credentials to malicious servers.
- 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-2026-48856?
CVE-2026-48856 is a high-severity vulnerability in Erlang OTP, published on 10 Jun 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 Erlang OTP inets (httpc_response module) allows Retrieve Embedded Sensitive Data.
The httpc client forwards the Authorization and Proxy-Authorization request headers to redirect targets without checking whether the redirect crosses an origin boundary. httpc_response:redirect/2 constructs the redirected request by updating only the host field of the header record; all other fields (including authorization and proxy_authorization) are copied verbatim. The redirect target host is never compared against the original host.
autoredirect defaults to true, so this affects all httpc callers that do not explicitly disable automatic redirects.
An attacker who controls a server that the victim contacts via httpc can issue a cross-origin 3xx redirect to a server they also control. The Authorization header (including Basic credentials derived from URL userinfo via httpc_request:handle_user_info/2) is forwarded to the redirect target, allowing credential theft. The same applies to the Proxy-Authorization header.
This vulnerability is associated with program files lib/inets/src/http_client/httpc_response.erl.
This issue affects OTP from OTP 17.0 before OTP 27.3.4.19, OTP 28.5.0.8, and OTP 29.1.2, corresponding to inets from 5.10 before 9.3.2.8, 9.6.2.4, and 9.8.1. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.
Weakness: CWE-601
Which versions are affected by CVE-2026-48856?
It affects 2 products.
Products include Erlang Erlang\/Inets, Erlang Erlang\/Otp.
How do I fix CVE-2026-48856?
Upgrade to a fixed version.
Is CVE-2026-48856 being exploited?
There is no known exploitation of CVE-2026-48856 in the wild and no public exploit code.
Other vulnerabilities in Erlang OTP
- CVE-2026-28808 ScriptAlias CGI targets bypass directory auth in inets httpd (mod_auth vs mod_cgi path mismatch)
- CVE-2026-23941 Request smuggling via first-wins Content-Length parsing in inets httpd
- CVE-2026-48858 ftp client PASV response IP not validated against control peer, enabling SSRF and FTP bounce attacks
Sources
Also known as AZL-90120, DEBIAN-CVE-2026-48856, EEF-CVE-2026-48856, GHSA-m75x-4vwg-ggjh, UBUNTU-CVE-2026-48856.