Information disclosure in Cfug Dio

CVE-2026-103030

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.

Vulnerability class: Information Disclosure

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-103030?
CVE-2026-103030 is a high-severity vulnerability in Cfug Dio, classified under Information Disclosure. CVSS score: 7.5/10. Published 2026-10-13.
How severe is CVE-2026-103030?
High severity. CVSS v3 base score is 7.5 out of 10.