CVE-2025-4207
📋 TL;DR
A buffer over-read vulnerability in PostgreSQL's GB18030 encoding validation allows attackers to cause temporary denial of service by triggering process termination. This affects both PostgreSQL database servers and libpq client library. Systems running PostgreSQL versions before 17.5, 16.9, 15.13, 14.18, and 13.21 are vulnerable.
💻 Affected Systems
- PostgreSQL
- Applications using libpq
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Database server process crashes, causing temporary service disruption until automatic restart or manual intervention.
Likely Case
Temporary denial of service affecting database availability, potentially disrupting dependent applications.
If Mitigated
Minimal impact with proper monitoring and automatic restart mechanisms in place.
🎯 Exploit Status
Exploitation requires ability to provide database input using GB18030 encoding. Server exploitation requires database access; client exploitation requires control over libpq input.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: PostgreSQL 17.5, 16.9, 15.13, 14.18, and 13.21
Vendor Advisory: https://www.postgresql.org/support/security/CVE-2025-4207/
Restart Required: Yes
Instructions:
1. Download appropriate patched version from PostgreSQL website. 2. Stop PostgreSQL service. 3. Install update following PostgreSQL upgrade procedures. 4. Restart PostgreSQL service. 5. Verify version with 'SELECT version();'
🔧 Temporary Workarounds
Disable GB18030 encoding
allRemove or restrict use of GB18030 encoding if not required for your application
ALTER DATABASE dbname SET client_encoding = 'UTF8';
Update application connection strings to use UTF8 encoding
Network segmentation
allRestrict database access to trusted applications and users only
Configure pg_hba.conf to limit connections
Implement firewall rules to restrict database port access
🧯 If You Can't Patch
- Implement strict input validation and sanitization for GB18030 encoded data
- Deploy monitoring and automatic restart mechanisms for PostgreSQL processes
🔍 How to Verify
Check if Vulnerable:
Connect to PostgreSQL and run: SELECT version(); Compare result with affected versions list.Check Version:
psql -c 'SELECT version();'Verify Fix Applied:
After patching, run: SELECT version(); Verify version is 17.5, 16.9, 15.13, 14.18, 13.21 or later.📡 Detection & Monitoring
Log Indicators:
- PostgreSQL process crashes/restarts
- Unexpected termination messages in PostgreSQL logs
- Connection errors related to encoding
Network Indicators:
- Unusual GB18030 encoded traffic to PostgreSQL port
- Multiple failed connection attempts followed by service disruption
SIEM Query:
source="postgresql.log" AND ("crash" OR "terminated" OR "segmentation fault")