CVE-2026-5708: AWS RES Privilege Escalation Vulnerability

CVE-2026-5708 Overview

CVE-2026-5708 is a privilege escalation vulnerability affecting AWS Research and Engineering Studio (RES) prior to version 2026.03. The flaw exists in the session creation component where unsanitized control of user-modifiable attributes allows an authenticated remote user to escalate privileges, assume the virtual desktop host instance profile permissions, and interact with AWS resources and services via a crafted API request.

This vulnerability is classified under CWE-915 (Improperly Controlled Modification of Dynamically-Determined Object Attributes), commonly known as a Mass Assignment vulnerability. This class of weakness occurs when an application allows users to modify object attributes that should be restricted, potentially enabling attackers to manipulate security-critical properties.

Critical Impact
Authenticated attackers can escalate privileges and assume virtual desktop host instance profile permissions, potentially gaining unauthorized access to AWS resources and services across the affected environment.

Affected Products

AWS Research and Engineering Studio (RES) versions prior to 2026.03

Discovery Timeline

April 6, 2026 - CVE-2026-5708 published to NVD
April 7, 2026 - Last updated in NVD database

Technical Details for CVE-2026-5708

Vulnerability Analysis

The vulnerability resides in the session creation component of AWS Research and Engineering Studio. When users create or modify sessions, the application fails to properly validate and sanitize user-controllable attributes. This lack of input sanitization allows authenticated users to inject or modify attributes that should be protected, ultimately enabling them to assume elevated permissions associated with the virtual desktop host instance profile.

The attack requires authentication, meaning an attacker must first have valid credentials to the RES environment. However, once authenticated, even a low-privileged user can exploit this flaw to gain access to AWS resources and services that would normally be restricted based on their role. This represents a significant breach of the principle of least privilege and could lead to unauthorized data access, resource manipulation, or further lateral movement within the AWS environment.

Root Cause

The root cause is the improper validation of user-modifiable attributes during session creation. The session creation component does not adequately restrict which object attributes can be modified by users, allowing attackers to manipulate security-sensitive properties. This is a classic Mass Assignment vulnerability (CWE-915) where the application blindly accepts user input for object attribute modification without proper allowlisting or validation of permissible fields.

Attack Vector

The attack is conducted remotely over the network and requires only low-level authentication. An attacker with valid credentials to the AWS Research and Engineering Studio can craft a malicious API request to the session creation endpoint. By including manipulated attribute values in this request, the attacker can modify properties that control privilege levels and instance profile associations.

The exploitation flow involves:

An authenticated user identifies the session creation API endpoint
The attacker crafts a request with modified attributes targeting privilege-related properties
Due to insufficient validation, the malicious attributes are accepted and processed
The attacker's session assumes the virtual desktop host instance profile permissions
With these elevated permissions, the attacker can interact with AWS resources and services beyond their authorized scope

For technical details on the vulnerability mechanism, refer to the AWS Security Bulletin 2026-014 and the GitHub Issue Tracker Entry.

Detection Methods for CVE-2026-5708

Indicators of Compromise

Unusual API requests to session creation endpoints with unexpected or non-standard attribute parameters
Users accessing AWS resources or services beyond their typical authorization scope
Session profile associations that do not match expected user permission levels
Anomalous activity originating from virtual desktop host instances

Detection Strategies

Monitor API logs for session creation requests containing suspicious or unexpected attribute modifications
Implement alerting for privilege escalation patterns, particularly users assuming instance profile permissions
Review AWS CloudTrail logs for unauthorized access attempts to resources outside normal user workflows
Correlate session creation events with subsequent AWS API calls to identify privilege abuse patterns

Monitoring Recommendations

Enable detailed logging for all RES session creation and modification events
Configure AWS CloudTrail to capture and alert on sensitive API operations performed by RES instance profiles
Implement anomaly detection for user activity that deviates from established baseline behavior
Regularly audit instance profile permissions and their associations with virtual desktop sessions

How to Mitigate CVE-2026-5708

Immediate Actions Required

Upgrade to AWS Research and Engineering Studio version 2026.03 or later immediately
Apply the corresponding mitigation patch if upgrading is not immediately feasible
Review recent session creation logs for potential exploitation attempts
Audit AWS CloudTrail for any unauthorized resource access that may indicate prior exploitation

Patch Information

AWS has released version 2026.03 of Research and Engineering Studio to address this vulnerability. Users are strongly advised to upgrade to this version to remediate the issue. For environments where immediate upgrade is not possible, AWS has provided a mitigation patch that can be applied to existing deployments.

For detailed patch information and upgrade instructions, refer to:

Workarounds

Apply the AWS-provided mitigation patch if immediate upgrade to version 2026.03 is not feasible
Implement additional network segmentation to limit the scope of potential privilege escalation
Restrict API access to the session creation endpoint using IAM policies where possible
Monitor and alert on all session creation activities until the patch can be applied

bash

# Verify current RES version and plan upgrade
# Check your deployment version against the patched release 2026.03
# Review AWS Security Bulletin 2026-014 for environment-specific mitigation steps