Vulnerabilities in pkg:npm/@powersync/service-core

PACKAGE
Advisory Identifier: GHSA-q6wc-xx4m-92fj
Advisory Summary

CVE-2026-30870 is a MODERATE (CVSS 6.5) some sync filters ignored on vulnerability (CWE-285: Improper Authorization) affecting PowerSync libraries in the npm ecosystem. The issue involves some sync filters ignored on 1.20.0 using `config.edition: 3`. Remediation is available by upgrading affected packages to version 1.20.1, 0.33.0.

1 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:npm/@powersync/service-core

1 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:npm/@powersync/service-core. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-q6wc-xx4m-92fj CVE-2026-30870 MODERATE PowerSync: Some sync filters ignored on 1.20.0 using `config.edition: 3`

CVE-2026-30870 at a Glance

CVE Identifier CVE-2026-30870
GHSA Identifier GHSA-q6wc-xx4m-92fj
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-285: Improper Authorization
Affected Product PowerSync
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 6.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-30870

To remediate this vulnerability, upgrade all affected PowerSync dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@powersync/service-core fixed: 1.20.1
npm install @powersync/service-core@1.20.1
@powersync/service-sync-rules fixed: 0.33.0
npm install @powersync/service-sync-rules@0.33.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

npm ls @powersync/service-core

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-30870, inspect your project dependencies using npm:

npm ls @powersync/service-core

Analyze the terminal output to locate any version of PowerSync in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.20.1), your application is affected.

Note: The npm ls @powersync/service-core command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-285: Improper Authorization, where the product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. In PowerSync, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact In version **1.20.0**, when using new sync streams with `config.edition: 3`, certain subquery filters were ignored when determining which data to sync to users. Depending on the sync stream configuration, this could result in authenticated users syncing data that should have been restricted. Only queries that gate synchronization using subqueries without partitioning the result set are affected. Not affected: * Sync rules (bucket_definitions) * Sync streams using `config.edition: 2` * No data is exposed without authenticating ### Patches The issue is **fixed in 1.20.1**. Restarting the service with the new version is sufficient - no reprocessing of sync streams is required. Any data that users erroneously synced will be automatically removed from those devices when they connect again. We have updated all affected PowerSync Cloud instances to the fixed version, and are reaching out to affected customers. For self-hosted PowerSync instances, update to the latest version and restart. ### Affected queries Subqueries used only to determine whether or not a table should be synced (without partitioning the data itself) are affected. Examples: ```sql -- Goal: Sync a table only to admin users -- 1.20.0: all authenticated users would sync this table SELECT * FROM sensitive_table WHERE auth.user_id() IN (SELECT user_id FROM admins) SELECT * FROM sensitive_table WHERE 1 IN (SELECT 1 FROM users WHERE id = auth.user_id() AND is_admin = TRUE) -- Goal: Sync a table only if authorized -- 1.20.0: all authenticated users would sync this table SELECT * FROM sensitive_table WHERE 'sensitive_table' IN (SELECT table_name FROM synced_table WHERE "user" = auth.user_id()) SELECT * FROM sensitive_table WHERE 'sensitive_table' IN auth.parameter('allowed_tables') ``` Queries that partition data (for example `SELECT * FROM sensitive_table WHERE owner IN (SELECT id FROM users WHERE is_admin AND id = auth.user_id())`) are not affected by this issue.

CVE-2026-30870 Affected PowerSync Versions

2 component(s)
Fixed Versions:
1.20.10.33.0
Product / Package Ecosystem Affected Versions Fixed Version
@powersync/service-core
npm
≥ 1.20.0
< 1.20.1
All 1 versions
1.20.0
1.20.1
@powersync/service-sync-rules
npm
≥ 0.32.0
< 0.33.0
All 1 versions
0.32.0
0.33.0

References

Frequently Asked Questions

What is CVE-2026-30870?
CVE-2026-30870 is a security vulnerability in PowerSync involving Some sync filters ignored on 1.20.0 using `config.edition: 3` under CWE-285: Improper Authorization.
Which PowerSync versions are affected?
Affected versions include releases prior to 1.20.1, 0.33.0 across affected packages: @powersync/service-core, @powersync/service-sync-rules.
What version fixes CVE-2026-30870?
Upgrading to 1.20.1, 0.33.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @powersync/service-core affected?
Yes, @powersync/service-core is affected in releases prior to 1.20.1. Upgrade your dependency to 1.20.1 or later.
Is @powersync/service-sync-rules affected?
Yes, @powersync/service-sync-rules is affected in releases prior to 0.33.0. Upgrade your dependency to 0.33.0 or later.
What is the CVSS score of CVE-2026-30870?
CVE-2026-30870 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-30870?
CVE-2026-30870 is classified under CWE-285: Improper Authorization (The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.).
How can I check npm dependencies for CVE-2026-30870?
Run the dependency tree command: 'npm ls @powersync/service-core'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q6wc-xx4m-92fj",
  "modified" : "2026-03-23T17:29:15Z",
  "published" : "2026-03-07T02:23:24Z",
  "aliases" : [ "CVE-2026-30870" ],
  "summary" : "PowerSync: Some sync filters ignored on 1.20.0 using `config.edition: 3`",
  "details" : "### Impact\n\nIn version **1.20.0**, when using new sync streams with `config.edition: 3`, certain subquery filters were ignored when determining which data to sync to users.\n\nDepending on the sync stream configuration, this could result in authenticated users syncing data that should have been restricted.\n\nOnly queries that gate synchronization using subqueries without partitioning the result set are affected.\n\nNot affected:\n * Sync rules (bucket_definitions)\n * Sync streams using `config.edition: 2`\n * No data is exposed without authenticating\n\n### Patches\n\nThe issue is **fixed in 1.20.1**. Restarting the service with the new version is sufficient - no reprocessing of sync streams is required.\n\nAny data that users erroneously synced will be automatically removed from those devices when they connect again.\n\nWe have updated all affected PowerSync Cloud instances to the fixed version, and are reaching out to affected customers.\n\nFor self-hosted PowerSync instances, update to the latest version and restart.\n\n### Affected queries\n\nSubqueries used only to determine whether or not a table should be synced (without partitioning the data itself) are affected. Examples:\n\n```sql\n-- Goal: Sync a table only to admin users\n-- 1.20.0: all authenticated users would sync this table\nSELECT * FROM sensitive_table WHERE auth.user_id() IN (SELECT user_id FROM admins)\nSELECT * FROM sensitive_table WHERE 1 IN (SELECT 1 FROM users WHERE id = auth.user_id() AND is_admin = TRUE)\n\n-- Goal: Sync a table only if authorized\n-- 1.20.0: all authenticated users would sync this table\nSELECT * FROM sensitive_table WHERE 'sensitive_table' IN (SELECT table_name FROM synced_table WHERE \"user\" = auth.user_id())\nSELECT * FROM sensitive_table WHERE 'sensitive_table' IN auth.parameter('allowed_tables')\n```\n\nQueries that partition data (for example `SELECT * FROM sensitive_table WHERE owner IN (SELECT id FROM users WHERE is_admin AND id = auth.user_id())`) are not affected by this issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@powersync/service-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.20.0"
      }, {
        "fixed" : "1.20.1"
      } ]
    } ],
    "versions" : [ "1.20.0" ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@powersync/service-sync-rules"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.32.0"
      }, {
        "fixed" : "0.33.0"
      } ]
    } ],
    "versions" : [ "0.32.0" ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/powersync-ja/powersync-service/security/advisories/GHSA-q6wc-xx4m-92fj"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-30870"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/powersync-ja/powersync-service"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-285" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-07T02:23:24Z",
    "nvd_published_at" : "2026-03-10T17:40:14Z"
  }
}