CVE-2026-108258
Description
A flaw was found in Shiny. The bookmark restore functionality fails to properly validate client-supplied state identifiers, resulting in a path traversal vulnerability. An unauthenticated remote attacker can exploit this flaw by submitting directory traversal sequences or absolute paths to access files outside the intended bookmark storage directory. In certain application configurations, this issue can also enable an attacker to copy and expose arbitrary files on the server, leading to information disclosure.
Statement
This vulnerability is evaluated as Moderate severity because standard deployments restrict path traversal behavior to checking the presence of specific predetermined file names, preventing arbitrary filesystem disclosure. Broader file exfiltration requires non-default application designs that concurrently utilize server-side bookmark storage and file upload controls. Additionally, Shiny for Python is not provided as an integrated service within Red Hat platforms, restricting potential impact to user-managed environments running custom applications.
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
The attacker may be able to create or overwrite critical files that are used to execute code, such as programs or libraries.
Integrity
Technical Impact: Modify Files or Directories
The attacker may be able to overwrite or create critical files, such as programs, libraries, or important data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, appending a new account at the end of a password file may allow an attacker to bypass authentication.
Confidentiality
Technical Impact: Read Files or Directories
The attacker may be able to read the contents of unexpected files and expose sensitive data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, by reading a password file, the attacker could conduct brute force password guessing attacks in order to break into an account on the system.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
The attacker may be able to overwrite, delete, or corrupt unexpected critical files such as programs, libraries, or important data. This may prevent the product from working at all and in the case of protection mechanisms such as authentication, it has the potential to lock out product users.
Frequently Asked Questions
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