How severe is GHSA-q6wc-xx4m-92fj?

GHSA-q6wc-xx4m-92fj has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-q6wc-xx4m-92fj?

GHSA-q6wc-xx4m-92fj affects the following packages: @powersync/service-core (npm), @powersync/service-sync-rules (npm). Ecosystems affected: npm.

How do I fix GHSA-q6wc-xx4m-92fj?

Update @powersync/service-core to 1.20.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-q6wc-xx4m-92fj is resolved across your whole dependency graph.

How do I detect GHSA-q6wc-xx4m-92fj in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @powersync/service-core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-q6wc-xx4m-92fj if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-q6wc-xx4m-92fj?

O3 pinpoints whether GHSA-q6wc-xx4m-92fj is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-q6wc-xx4m-92fj actively exploited in the wild?

No public exploit code has been indexed for GHSA-q6wc-xx4m-92fj yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-q6wc-xx4m-92fj?

GHSA-q6wc-xx4m-92fj has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 10th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-q6wc-xx4m-92fj?

GHSA-q6wc-xx4m-92fj is classified as CWE-285 (CWE-285). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-q6wc-xx4m-92fj published, and has it been updated?

GHSA-q6wc-xx4m-92fj was published on March 7, 2026 and was last updated on March 23, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

GHSA-q6wc-xx4m-92fj

MEDIUM

PowerSync: Some sync filters ignored on 1.20.0 using `config.edition: 3`

Also known asCVE-2026-30870

Published

Mar 7, 2026

Updated

Mar 23, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk10th percentile+0.16%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

2 pkgs affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

@powersync/service-corenpm

575downloads / week

@powersync/service-sync-rulesnpm

30Kdownloads / week

Description

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:

-- 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.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@powersync/service-core`	≥ 1.20.0&&< 1.20.1	1.20.1
📦npm	`@powersync/service-sync-rules`	≥ 0.32.0&&< 0.33.0	0.33.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @powersync/service-core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @powersync/service-core to 1.20.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-q6wc-xx4m-92fj is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-q6wc-xx4m-92fj is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-q6wc-xx4m-92fj. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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**. Re

O3 Security · Impact-Aware SCA

Is GHSA-q6wc-xx4m-92fj in your dependencies?

O3 detects GHSA-q6wc-xx4m-92fj across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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