Dart Software Development KitApplication · Dart

CVE-2022-3095

CRITICAL · 9.8 CVSS v3.1 Published 2022-10-27
Fix available
A fix is available. Upgrade to 2.18.0 / 3.3.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Dart URI class uses RFC 3986 syntax for backslash parsing, which differs from the WhatWG URL standard used by web browsers. This causes URIs containing backslashes (e.g., http://example.com\evil.com) to be parsed differently—Dart interprets the backslash as part of the path, while browsers interpret it as part of the hostname. This discrepancy can enable authentication bypass in web applications that rely on URI parsing for security decisions.

MitigationUpdate Dart to version 2.18 or later, or Flutter to version 3.30 or later, to align URI parsing with WhatWG standards.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Dart Software Development KitApplication
Affected:< 2.18.0
FlutterApplication
Affected:< 3.3.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Dart SDK version
    Run `dart --version` in your terminal or inspect the pubspec.lock file for the sdk version entry
    Affected if The reported version is earlier than 2.18.0 (e.g., 2.17.x, 2.16.x, etc.)
  2. Check Flutter SDK version
    Run `flutter --version` in your terminal, or check the Flutter installation directory for the version file
    Affected if The reported version is earlier than 3.3.3 (e.g., 3.3.2, 3.3.1, 3.3.0, etc.)
  3. Identify if your application parses user-supplied URIs
    Review your codebase for uses of the Uri class or url parsing logic that processes input from external sources (query parameters, headers, form inputs)
    Affected if Your code uses Dart's Uri class to parse and make security decisions (such as allowlists, authentication checks, or redirection logic) on URIs that may contain backslashes

You are affected if you run Dart SDK below 2.18.0 or Flutter below 3.3.3 AND your application relies on Dart URI parsing for security decisions involving URIs with backslashes.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.18.0 / 3.3.3 or later
Fixed in 2.18.03.3.3
Interim mitigation

Update Dart to version 2.18 or later, or Flutter to version 3.30 or later, to align URI parsing with WhatWG standards.

Recommended fix Moderate confidence

Dart SDK 2.18.0 or Flutter 3.3.3

  1. Check current Dart SDK version using: dart --version
  2. Check current Flutter version using: flutter --version
  3. For Dart-only projects: Run 'dart pub upgrade' or download Dart SDK 2.18.0 from dart.dev
  4. For Flutter projects: Run 'flutter upgrade' to update to Flutter 3.3.3 or later
  5. Verify the update was successful by re-running the version commands
  6. Test URI parsing functionality in your application to confirm the backslash handling is now compliant with WhatWG standards
Caveat Minimal; the upgrade primarily fixes URI parsing compliance; verify any custom URI handling code

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Dart Software Development Kit Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,920
Get the upgrade done

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Scan for this in your stack

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dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-3095 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data