CVE-2026-63116

CVE-2026-63116 is a high-severity missing authorization vulnerability in @deepstream/server (npm), affecting versions = 10.1.0. It is fixed in 10.1.1.

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Summary

deepstream: PATCH_MULTI action bypasses Valve permission system allowing unauthorized record writes

The RECORD_ACTION.PATCH_MULTI action is not registered in the Valve permission system's RULES_MAP (src/services/permission/valve/rules-map.ts). When ConfigPermission.canPerformAction() is called for a PATCH_MULTI message, getRulesForMessage() returns null because the action is missing from the map. This triggers an unconditional allow (callback(..., null, true)), completely bypassing all configured Valve permission rules.

Any authenticated user, regardless of their configured permissions, can write arbitrary data to any record using the PATCH_MULTI action.

Root Cause

In src/services/permission/valve/rules-map.ts lines 38-54, the RULES_MAP[TOPIC.RECORD].actions dictionary maps record actions to permission rule types. The actions registered include: SUBSCRIBE, SUBSCRIBEANDHEAD, SUBSCRIBEANDREAD, READ, HEAD, LISTEN, CREATE, UPDATE, PATCH, NOTIFY, DELETE, ERASE. However, RECORD_ACTION.PATCH_MULTI is absent from this map.

When getRulesForMessage() at line 86-99 encounters an action not in the map, it returns null. In config-permission.ts at line 88-93, when ruleSpecification === null, the callback is invoked with true (allow) unconditionally.

Attack Chain

  1. Attacker authenticates with any valid credentials (even a minimal-privilege user)
  2. Attacker sends a WebSocket message: {topic: RECORD, action: PATCH_MULTI, name: "admin/secret-record", parsedData: [{path: "role", data: "admin"}]}
  3. message-processor.ts:68 invokes permission check
  4. config-permission.ts:89 → getRulesForMessage() returns null for PATCH_MULTI
  5. config-permission.ts:92 → unconditional ALLOW
  6. Record transition applies the operations, arbitrary record is modified

Affected Versions

All versions that include PATCH_MULTI support with the Valve (ConfigPermission) permission system. The PATCH_MULTI action was added in commit 82ffa8119d8f4a8242ac5c3507469a22de746b65 but was never registered in RULES_MAP.

Credit

Vulnerability discovered by Zhixi "Jace" Sun of ASM/VI at TikTok.

Impact

  • Complete Valve permission bypass for record writes, all configured permission rules are irrelevant
  • Any authenticated user can overwrite any record, including admin-only records
  • Mass record overwrites can destroy application state, corrupt sessions, cause service outage
  • Only exploitable when permission.type is set to config (Valve), the recommended production configuration per deepstream documentation
  • Default permission type none (OpenPermission) allows everything already, so default deployments are unaffected
Proof of Concept
// Connect as a minimal-privilege user
const { DeepstreamClient } = require('@deepstream/client');
const client = new DeepstreamClient('localhost:6020');
await client.login({ username: 'restricted-user', password: 'password' });

// This should be blocked by Valve permissions but isn't:
// Send raw PATCH_MULTI message to bypass all permission rules
const connection = client.getConnection();
connection.sendMessage({
  topic: 0x52, // TOPIC.RECORD
  action: 0x50, // RECORD_ACTION.PATCH_MULTI (check actual enum value)
  name: 'admin/protected-record',
  parsedData: [
    { path: 'permissions', data: 'admin' },
    { path: 'secret', data: 'overwritten' }
  ]
});

The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.

CVE-2026-63116 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (10.1.1); upgrading removes the vulnerable code path.

Affected versions

@deepstream/server (= 10.1.0)

Security releases

@deepstream/server → 10.1.1 (npm)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Add PATCH_MULTI to the RULES_MAP in src/services/permission/valve/rules-map.ts:

[RECORD_ACTION.PATCH_MULTI]: RULE_TYPES.WRITE,

This maps PATCH_MULTI operations to the same WRITE permission rule that governs UPDATE and PATCH.

Frequently Asked Questions

  1. What is CVE-2026-63116? CVE-2026-63116 is a high-severity missing authorization vulnerability in @deepstream/server (npm), affecting versions = 10.1.0. It is fixed in 10.1.1. The application does not perform an authorization check before performing a sensitive operation.
  2. How severe is CVE-2026-63116? CVE-2026-63116 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
  3. Which versions of @deepstream/server are affected by CVE-2026-63116? @deepstream/server (npm) versions = 10.1.0 is affected.
  4. Is there a fix for CVE-2026-63116? Yes. CVE-2026-63116 is fixed in 10.1.1. Upgrade to this version or later.
  5. Is CVE-2026-63116 exploitable, and should I be worried? Whether CVE-2026-63116 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
  6. What actually determines whether CVE-2026-63116 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
  7. How do I fix CVE-2026-63116? Upgrade @deepstream/server to 10.1.1 or later.

Other vulnerabilities in @deepstream/server

CVE-IDSeverityPackage summary
CVE-2026-49252Critical@deepstream/server: deepstream is vulnerable to prototype pollution

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