CVE-2026-43891: dgtlmoon changedetection.io External Control of File Name or Path

Vulnerability summary

CVE-2026-43891 is a high (CVSS 7.5) External Control of File Name or Path vulnerability in dgtlmoon changedetection.io. EPSS estimates a 0.50% chance of exploitation in the next 30 days, higher than 41.5% of scored vulnerabilities. 2 public exploits are recorded.

Timeline

1. 12-05-2026
   PublishedVulnerability first disclosed.
2. 13-05-2026
   Last modifiedVulnerability information updated.

Description

changedetection.io is a free open source web page change detection tool. Prior to 0.55.1, the vulnerability is caused by trusting attacker-controlled snapshot paths restored from backup files. The vulnerable flow starts in the backup restore logic. When a backup ZIP is restored, the application extracts the archive and copies each restored watch UUID directory directly into the live datastore using shutil.copytree(entry.path, dst_dir). This preserves attacker-controlled files inside the restored watch directory, including history.txt. After restore, the application parses history.txt in the watch history property and returns the contents of the targeted local file. This vulnerability is fixed in 0.55.1.

• CWE-73External Control of File Name or PathThe product allows user input to control or influence paths or file names that are used in filesystem operations.