Description
The implementation of backslash parsing in the Dart URI class for versions prior to 2.18 and Flutter versions prior to 3.30 differs from the WhatWG URL standards. Dart uses the RFC 3986 syntax, which creates incompatibilities with the '\' characters in URIs, which can lead to auth bypass in webapps interpreting URIs. We recommend updating Dart or Flutter to mitigate the issue.
References (1)
Core 1
Core References
Release Notes, Third Party Advisory
https://github.com/dart-lang/sdk/blob/master/CHANGELOG.md#2182---2022-09-28
Scores
CVSS v3
9.8
EPSS
0.0087
EPSS Percentile
54.2%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
total
Details
CWE
CWE-20
Status
published
Products (2)
dart/dart_software_development_kit
< 2.18.0
flutter/flutter
< 3.3.3
Published
Oct 27, 2022
Tracked Since
Feb 18, 2026