CVE intelligence and bounded remediation

CVE-2026-27704 — The Dart and Flutter SDKs provide software development kits for the Dart programming language

High CVSS 7.5

The Dart and Flutter SDKs provide software development kits for the Dart programming language. In versions of the Dart SDK prior to 3.11.0 and the Flutter SDK prior to version 3.41.0, when the pub client (`dart pub` and `flutter pub`) extracts a package in the pub cache, a malicious package archive can have files extracted outside the destination directory in the `PUB_CACHE`. A fix has been landed in commit 26c6985c742593d081f8b58450f463a584a4203a. By normalizing the file path before writing file, the attacker can no longer traverse up via a symlink. This patch is released in Dart 3.11.0 and Flutter 3.41.0.vAll packages on pub.dev have been vetted for this vulnerability. New packages are no longer allowed to contain symlinks. The pub client itself doesn't upload symlinks, but duplicates the linked entry, and has been doing this for years. Those whose dependencies are all from pub.dev, third-party repositories trusted to not contain malicious code, or git dependencies are not affected by this vulnerability.

Severity
High
CVSS
7.5 (3.1)
Published
2026-02-25
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-22

Affected products

  • dart / dart_software_development_kit
  • flutter / flutter

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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