CVE-2026-103030 Dio: Cross-origin redirect leaks sensitive request headers in `dio_http2_adapter`
A malicious server can leak sensitive headers like Authorization and Cookies to a different origin via cross-origin redirects in the Dio HTTP client.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-103030?
CVE-2026-103030 is a high-severity vulnerability in cfug dio, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Dio is a powerful HTTP client for Dart and Flutter. From 1.0.0 until 2.8.0, dio_http2_adapter follows redirects in Http2Adapter._fetch by copying the original RequestOptions.headers into the redirected HTTP/2 request without comparing the source and destination origins. A server contacted by an application can return a cross-origin Location redirect to a different-origin destination, which then receives preserved Authorization, Cookie, and Proxy-Authorization headers because RequestOptions.copyWith retains the full header map. The issue applies when applications use Http2Adapter for authenticated requests, and redirect following is enabled by default. This issue is fixed in version 2.8.0.
Weakness: CWE-200
Which versions are affected by CVE-2026-103030?
2 open source packages ship an affected version, including dio_http2_adapter.
| Package | Affected | Fixed in |
|---|---|---|
dio_http2_adapter Pub | From 1.0.0 | 2.8.0 |
dio_http2_adapter Pub | From 1.0.0 | 2.8.0 |
How do I fix CVE-2026-103030?
Upgrade dio_http2_adapter to 2.8.0 or later.
Is CVE-2026-103030 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-103030 exists.
Sources
Also known as GHSA-cr65-55v9-xhvv.