CVE-2026-13511: VoltAgent Auth Bypass Vulnerability

CVE-2026-13511 Overview

CVE-2026-13511 is an improper authorization vulnerability in VoltAgent versions up to 2.1.17. The flaw resides in the handleGetMemoryConversation function within packages/server-core/src/handlers/memory.handlers.ts, part of the Memory REST API component. An authenticated remote attacker can manipulate the conversationId argument to access conversation memory outside their authorization boundary. The weakness is classified under [CWE-266: Incorrect Privilege Assignment]. The exploit has been publicly disclosed, though exploitation is characterized as high complexity. A pull request addressing the issue is pending acceptance upstream.

Critical Impact
Authenticated remote attackers can bypass authorization checks on VoltAgent Memory REST API endpoints to read conversation data belonging to other users or sessions.

Affected Products

VoltAgent up to and including version 2.1.17
Component: Memory REST API (packages/server-core)
Function: handleGetMemoryConversation

Discovery Timeline

2026-06-28 - CVE-2026-13511 published to NVD
2026-06-29 - Last updated in NVD database

Technical Details for CVE-2026-13511

Vulnerability Analysis

The vulnerability affects VoltAgent, an open-source framework for building AI agents. The handleGetMemoryConversation handler serves memory conversation records through a REST endpoint. The handler accepts a conversationId parameter but fails to enforce that the requesting principal owns or has authorization to view the referenced conversation.

An authenticated attacker with low privileges can supply a conversationId belonging to another user or session. The handler returns the conversation contents without validating ownership. This exposes stored agent memory, which may contain prompts, tool outputs, and user data. The attack is remote and requires no user interaction, though the disclosed exploit path is high complexity.

Root Cause

The root cause is a missing authorization check between authentication and data retrieval. Authentication confirms the caller's identity, but the handler does not confirm the caller is entitled to the specific conversationId requested. This pattern is a classic Insecure Direct Object Reference aligned with [CWE-266].

Attack Vector

The attack vector is network-based against exposed VoltAgent Memory REST API endpoints. An attacker authenticates as a low-privileged user, then iterates or guesses conversationId values on the memory conversation endpoint. Successful requests return conversation memory owned by other principals. No code examples are provided in verified sources; refer to the GitHub Issue #1315 and GitHub Pull Request #1317 for the exact code path and proposed fix.

Detection Methods for CVE-2026-13511

Indicators of Compromise

Unusual volume of GET requests to Memory REST API conversation endpoints from a single authenticated principal.
Sequential or enumerated conversationId values appearing in access logs from one client.
HTTP 200 responses for conversationId values not previously associated with the requesting user session.

Detection Strategies

Instrument the VoltAgent server to log the authenticated principal alongside every conversationId accessed and alert on mismatches.
Deploy web application firewall rules that rate-limit and profile access patterns against /memory/conversations/* routes.
Correlate authentication events with subsequent memory API calls to identify enumeration behavior.

Monitoring Recommendations

Retain and review VoltAgent application logs with principal-to-object mapping for at least 90 days.
Alert on any principal accessing more distinct conversationId values within a short window than a baseline threshold.
Monitor egress from VoltAgent hosts for unexpected bulk data transfers that may indicate memory scraping.

How to Mitigate CVE-2026-13511

Immediate Actions Required

Restrict network access to VoltAgent Memory REST API endpoints so only trusted clients can reach them.
Audit existing accounts and revoke API credentials that are no longer required.
Review access logs for prior enumeration of conversationId values and treat matches as potential data exposure.

Patch Information

An official fix is pending. The upstream Pull Request #1317 awaits acceptance and addresses the missing authorization check in handleGetMemoryConversation. Monitor the VoltAgent repository and update to a release incorporating the fix once merged. Additional tracking information is available at VulDB CVE-2026-13511.

Workarounds

Place VoltAgent behind an authenticating reverse proxy that enforces per-user authorization on conversationId paths.
Apply the patch from Pull Request #1317 as a local build if you cannot wait for an upstream release.
Use unguessable, high-entropy conversationId values to raise the cost of enumeration until the authorization check is in place.

bash

# Example reverse proxy rule (nginx) restricting Memory API to internal networks
location /memory/ {
    allow 10.0.0.0/8;
    deny all;
    proxy_pass http://voltagent_backend;
}