VulnerabilityPublished 25 Feb 2026

CVE-2026-27704: dart-lang sdk · Path Traversal

Affects dart-lang sdkSource CVE Database V5

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Not known to be exploited · CVSS 6.6 Medium : upgrade to 3.11.0 when convenient.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score

6.6Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.11.0, 3.41.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: High
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: Unreported

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: Unreported: Based on threat intelligence sources each of the following must apply: · No knowledge of publicly available proof-of-concept · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade sdk and dart/sdk to 3.11.0; flutter to 3.41.0.

Affected software

Product	Affected	Fixed in
dart-langsdk	Affected <3.11.0	Fixed in 3.11.0
dart-langflutter	Affected <3.41.0	Fixed in 3.41.0
Pubdart/sdk`pkg:pub/dart/sdk`Other threats	Affected <3.11.0	Fixed in 3.11.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to Dart SDK version 3.11.0 or later and Flutter SDK version 3.41.0 or later to apply the official patch that normalizes file paths during extraction.
Restrict package sources to trusted repositories such as pub.dev, which vets packages to exclude symlinks, or trusted git dependencies.
Implement strict controls and scanning on third-party or private package archives before use, including verifying absence of symlinks or path traversal payloads.
Use sandboxed or isolated environments for package extraction to limit potential damage from malicious archives.
Monitor file system changes in the PUB_CACHE directory and related paths for unusual activity indicative of exploitation attempts.
Educate developers and CI/CD operators about the risks of using untrusted packages and encourage best practices in dependency management.
Consider integrating automated security scanning tools that detect path traversal or symlink abuse in package archives prior to installation.

Description

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.

Impact

The vulnerability allows an attacker to write files outside the intended package cache directory during package extraction, potentially leading to unauthorized file creation or modification on the host system. This can compromise the confidentiality and integrity of the affected environment, especially if the attacker can place malicious executables, configuration files, or scripts in sensitive locations. Since the pub client operates without requiring user interaction or privileges, a remote attacker who can supply a malicious package archive could exploit this vulnerability to affect developers or CI/CD systems that automatically fetch and extract Dart or Flutter packages. The impact is particularly significant for organizations that consume untrusted or third-party Dart packages outside of vetted repositories. However, the risk is mitigated for users relying solely on pub.dev or trusted git dependencies. The vulnerability does not directly affect availability but can facilitate further attacks or persistence mechanisms if exploited. Overall, the threat could lead to supply chain compromise and unauthorized code execution in development environments.

Summary

CVE-2026-27704 is a path traversal vulnerability classified under CWE-22 affecting the Dart and Flutter SDKs before versions 3.11.0 and 3.41.0, respectively. The vulnerability arises during the extraction process of package archives by the pub client (`dart pub` and `flutter pub`) into the PUB_CACHE directory. A maliciously crafted package archive can exploit improper pathname normalization to escape the intended extraction directory by leveraging symbolic links, thereby writing files outside the restricted directory. This can lead to unauthorized file creation or overwriting on the host system, potentially compromising confidentiality or integrity of the environment where the SDK is used. The root cause was the lack of normalization of file paths before extraction, allowing traversal sequences to bypass directory restrictions. The fix, implemented in commit 26c6985c742593d081f8b58450f463a584a4203a and released in Dart 3.11.0 and Flutter 3.41.0, normalizes file paths to prevent symlink traversal. Additionally, pub.dev enforces vetting of packages to exclude symlinks, and the pub client duplicates linked entries instead of uploading symlinks, reducing risk from official packages. Users relying on trusted third-party or git dependencies are not affected. The vulnerability has a CVSS 4.0 base score of 6.6, indicating medium severity with network attack vector, no privileges or user interaction required, and high confidentiality impact. No known exploits have been reported in the wild as of publication.

CWE-22Improper Limitation of a Pathname to a Restricted Directory (Path Traversal) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #6OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
Attack patterns
Path Traversal (opens in a new tab)
Using Slashes and URL Encoding Combined to Bypass Validation Logic (opens in a new tab)
Manipulating Web Input to File System Calls (opens in a new tab)
Using Escaped Slashes in Alternate Encoding (opens in a new tab)
Using Slashes in Alternate Encoding (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Mar 2026, 20:39 UTC

WeaknessesCWE-22

Technical details

References

Community reviews

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