CVE-2026-35397
Description
A flaw was found in Jupyter Server. An authenticated user can exploit a path traversal vulnerability in the REST API to escape the configured root directory (root_dir). By crafting a request to the /api/contents endpoint with encoded path components, an attacker can gain access to sibling directories whose names begin with the same prefix as the root_dir. This allows the attacker to read, write, and delete files in these accessible sibling directories, potentially leading to unauthorized data access and modification, especially in multi-tenant environments.
Statement
This Important flaw in Jupyter Server enables an authenticated user to bypass their configured root directory via a path traversal vulnerability in the REST API. This allows access to, and manipulation of, files within sibling directories that share a common prefix. The risk is elevated in multi-tenant Red Hat OpenShift AI environments where predictable directory naming conventions are often employed.
Mitigation
To mitigate this issue, ensure that directory names within Jupyter Server deployments do not share common prefixes with sibling directories. This operational control prevents authenticated users from exploiting the path traversal vulnerability to access unauthorized content. For example, avoid naming directories 'user1' and 'user10' if 'user' is a common prefix. This mitigation does not require service restarts or reloads.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.1 | 8.8 | 7.1 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | Low | High |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | Low | High | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L
NVD: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L
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 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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