Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-27696 is a high-severity SSRF (CWE-918) vulnerability in Webtechnologies Changedetection. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 44th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-27696 is a Server-Side Request Forgery (SSRF) vulnerability (CWE-918) affecting changedetection.io, a free open-source web page change detection tool, in versions prior to 0.54.1. The issue stems from the URL validation function `is_safe_valid_url()`, which fails to check the resolved IP address of watch URLs against private, loopback, or link-local address ranges. This allows the application to process and fetch arbitrary internal URLs without proper restrictions.
An attacker with authenticated access—or any user when no password is configured, which is the default—can exploit this by adding a watch for internal network URLs. The application then fetches these URLs server-side, stores the response content, and exposes it through the web UI, enabling full data exfiltration from internal services. The vulnerability has a CVSS v3.1 base score of 8.6 (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N), indicating high severity due to network accessibility, low complexity, and significant confidentiality impact in a changed scope.
The GitHub security advisory (GHSA-3c45-4pj5-ch7m) and associated commit (fe7aa38c651d73fe5f41ce09855fa8f97193747b) confirm that version 0.54.1 addresses the issue by improving URL validation to block unsafe IP ranges. Security practitioners should upgrade to 0.54.1 or later and consider enforcing authentication with strong passwords to limit exposure.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-8622
Vulnerability Data
changedetection.io is a free open source web page change detection tool. In versions prior to 0.54.1, changedetection.io is vulnerable to Server-Side Request Forgery (SSRF) because the URL validation function `is_safe_valid_url()` does not validate the resolved IP address of watch URLs…
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against private, loopback, or link-local address ranges. An authenticated user (or any user when no password is configured, which is the default) can add a watch for internal network URLs. The application fetches these URLs server-side, stores the response content, and makes it viewable through the web UI — enabling full data exfiltration from internal services. Version 0.54.1 contains a fix for the issue.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.3.6V1.5.3V5.3.2V10.4.7
Mitigating Controls (NIST 800-53 r5) AI
Information flow enforcement can restrict which destinations the server is allowed to contact on behalf of users.
Input validation directly stops untrusted URLs from being accepted and fetched without destination checks.
Boundary protection limits the network reach of server-initiated requests even if SSRF occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure development practices directly include input validation and destination allow-listing that prevent SSRF.
Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.
Vulnerability identification processes can discover and record SSRF flaws in web applications.
Network segmentation and egress controls can limit the damage from successful SSRF requests.