# 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.

- **Severity:** High 7.1 (`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`)
- **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:** Yes
- **Published:** 10 Jun 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-90120, DEBIAN-CVE-2026-48856, EEF-CVE-2026-48856, GHSA-m75x-4vwg-ggjh, UBUNTU-CVE-2026-48856

## 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 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2026-48856?

It affects 2 products.


Products: 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](https://insights.sbomify.com/CVE-2026-28808/): ScriptAlias CGI targets bypass directory auth in inets httpd (mod_auth vs mod_cgi path mismatch) (high 8.3)
- [CVE-2026-23941](https://insights.sbomify.com/CVE-2026-23941/): Request smuggling via first-wins Content-Length parsing in inets httpd (high 7.0)
- [CVE-2026-48858](https://insights.sbomify.com/CVE-2026-48858/): ftp client PASV response IP not validated against control peer, enabling SSRF and FTP bounce attacks (medium 6.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48856 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-48856 in the wild and no public exploit code.

Affected product: Erlang OTP. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-48856/ (Markdown: https://insights.sbomify.com/CVE-2026-48856/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48856
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48856
- OSV: https://osv.dev/vulnerability/CVE-2026-48856

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48856/
Summaries are generated and may contain mistakes; the official description above is the record.