High [CVE-2026-76172] URI parsing flaw enables server-side request forgery and redirects
This high-severity Red Hat Linux advisory covers CVE-2026-76172 affecting Migration Toolkit for Applications 8, Migration Toolkit for Containers, Multicluster Engine for Kubernetes.
Android app · Google Play
Monitor future Red Hat Linux CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.
Summary
fast-uri is a URI parser for Node.js. During parsing it runs a legacy decoding pass over the scheme component and never re-escapes the result, and serialization writes the scheme back out verbatim, unlike the host component which is re-escaped.
As a result an input whose scheme carries percent-encoded slashes parses as a scheme with no authority, so the parsed host and error are both undefined, yet resolving or normalizing that same input emits a network-path reference whose authority is attacker-chosen and re-parses to that host.
An application that allowlists on the parsed host, or treats a reference with no authority as safe to resolve against its base, gets the opposite of what it checked, giving an off-site redirect, server-side request forgery, or address-policy bypass.
The legacy decoder also expands non-standard escape forms, widening the issue past upstream filters, and control characters in the scheme can reach the output as raw carriage return and line feed. The affected versions are 2.3.1 up to but not including 2.4.5, 3.0.0 up to but not including 3.1.6, and 4.0.0 up to but not including 4.1.3.
The issue is fixed in 2.4.5, 3.1.6, and 4.1.3, which reject a scheme that is not valid after decoding. Users should upgrade to a patched version.
- 2.3.1
- 3.0.0
- 4.0.0
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
- 2.4.5
- 3.1.6
- 4.1.3
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation
Upgrade to a fixed release: 2.4.5, 3.1.6, 4.1.3. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.