Bugsink Pfadüberschreitung über event_id in ingestion

The vulnerability stems from the ingestion paths in Bugsink constructing file locations directly from untrusted eventid input without proper validation. A malicious actor can craft a specific eventid that bypasses intended directory restrictions, enabling them to write files outside the designated area. While a valid DSN is required to trigger the vulnerability, the ease of DSN discovery—particularly when included in frontend code—significantly broadens the potential attack surface. Successful exploitation could lead to data corruption, privilege escalation (if writable files are critical system components), and potentially even remote code execution depending on the file permissions and the context of the overwritten file.

Organizations utilizing Bugsink in environments where DSN credentials are not adequately protected are at heightened risk. This includes deployments with shared hosting configurations, legacy systems with hardcoded DSNs, and applications where DSNs are inadvertently exposed in frontend code. Any system relying on Bugsink for data ingestion should be considered potentially vulnerable.

• python / server: Examine Bugsink logs for unusual file creation or modification events. Look for patterns in event_id parameters that attempt to include directory traversal sequences (e.g., ../).

# Example: Check for suspicious file paths in Bugsink logs
import re
with open('bugsink.log', 'r') as f:
    for line in f:
        if re.search(r'event_id=.*[\/][\/].*', line):
            print(f'Potential Path Traversal attempt: {line}')

• generic web: Monitor access logs for requests to Bugsink endpoints with unusual or long event_id parameters. Check response headers for unexpected file content.

curl -I 'http://bugsink.example.com/ingest?event_id=../../../../etc/passwd' # Check for 403 or other error codes

1. 2025-07-29Disclosure

   disclosure

1. Reserviert2025-07-21
2. Veröffentlicht2025-07-29
3. Geändert2025-07-30
4. EPSS aktualisiert2026-03-23

The primary mitigation is to upgrade Bugsink to version 1.7.4 or later, which includes the necessary validation to prevent path traversal. If upgrading immediately is not feasible, consider restricting access to the DSN used by Bugsink. Ensure that the DSN is not exposed in frontend code or other publicly accessible locations. Implement strict file permissions on the ingestion directory to limit the impact of a successful attack. Monitor file system activity for unexpected modifications or creations within the ingestion directory.