CVE-2026-43891: changedetection.io: Arbitrary Local File Read via crafted backup restore

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-12 · updated 2026-10-26
Weakness: CWE-73

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.

Affected products

dgtlmoon changedetection.io: before 0.55.1 — fixed in 0.55.1

How to fix

Upgrade to a fixed version: dgtlmoon changedetection.io 0.55.1. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-43891 or the next vulnerability affects your stack