CVE-2016-0752 is a directory traversal vulnerability in Rails Ruby on Rails. CISA added it to the Known Exploited Vulnerabilities catalogue on 25 March 2022, which means attackers have used it in real attacks. Directory traversal vulnerability in Action View in Ruby on Rails allows remote attackers to read arbitrary files.
What this vulnerability means
Directory traversal in Ruby on Rails means an attacker can manipulate a request so the application resolves a file path outside the intended directory. In this case, the weakness is in Action View, which makes file-reading a confidentiality issue, not just a routing or parsing bug.
Because Rails is widely used in web applications, a traversal flaw can expose source files, configuration, templates, environment data, or other sensitive content that developers assumed was unreachable. The practical danger is that file-system boundaries enforced by the application can be bypassed even when the underlying host is otherwise protected.
For CVE records and authoritative metadata, use the CVE Program entry and the NIST National Vulnerability Database record rather than relying on summaries alone.
Why it is dangerous in web applications
Traversal flaws are especially dangerous when the affected component can be reached remotely and when the application handles user-controlled path fragments, template lookups, or file-serving logic. A successful attack can turn a normal request into arbitrary file disclosure, which often becomes a stepping stone to broader compromise.
The exposure is not limited to obvious documents. Secrets embedded in configuration files, credentials in environment files, deployment details, and application internals may all be accessible if the traversal reaches them. That makes the issue relevant to both application security and identity security, because disclosed secrets can unlock other systems after the initial read.
The most useful technical context for this class of bug is the broader path traversal and local file inclusion attack family. NHIMG’s Web Application Attacks Guide covers how traversal fits into the wider set of web file-access failures.
How organisations check exposure and reduce blast radius
Exposure assessment starts with knowing where Rails is deployed, which internet-facing applications use it, and whether any instances still rely on vulnerable releases. Organisations should compare their asset inventory against vendor advisories and the NVD and CVE Program records to confirm which systems need attention.
Where patching is delayed, compensating controls matter. Tighten request validation around path handling, restrict what the application can read on disk, remove unnecessary secrets from local files, and reduce exposure of the application itself to untrusted networks. For teams managing many vulnerabilities at once, NHIMG’s Vulnerability Management Guide is a useful reference for prioritisation and verification.
In practice, the biggest reduction in blast radius comes from assuming that file disclosure may expose credentials or tokens, not just harmless text. That is why secrets hygiene and least privilege around runtime files are part of the response, even though the vulnerability itself is a web application flaw.
Detection, remediation, and compromise review
Detection is strongest when logs, web traces, and file-access behaviour are reviewed together. Repeated requests with suspicious path separators, encoded traversal sequences, or unexpected file names can indicate probing, while access to sensitive files after the exposure window can indicate exploitation.
After remediation, the review should not stop at confirming the patch. If the application could read configuration or secret material, review whether credentials, sessions, API keys, signing material, or service account secrets may have been exposed and rotate them where necessary. NHIMG’s State of NHI & AI Agent Breach Report is a useful reminder that stolen secrets are often the real follow-on impact after initial access.
Because this issue is on CISA’s Known Exploited Vulnerabilities catalogue, the safest assumption is that exploitation is plausible in the wild. That makes post-patch review and secret rotation important parts of the response, not optional extras.
Risk and Threat Considerations
Directory traversal is dangerous because it can convert a simple request into unauthorised file disclosure. In a Rails application, that can expose templates, configuration, environment details, or secrets that materially widen the attacker’s next move.
Failure mechanism: The attacker manipulates path resolution so Action View reads a file outside the intended application scope, bypassing the developer’s file-access assumptions.
Impact: Confidential files may be disclosed, enabling credential theft, follow-on access to other systems, and deeper compromise if exposed secrets are reused elsewhere.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP ASVS, CIS Controls v8 and NIST SP 800-53 Rev 5 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP ASVS | V5 — File Handling | Directory traversal is a file-access flaw in a web application. |
| V16 — Security Logging and Error Handling | Traversal attacks are confirmed and reviewed through application logging and error traces. | |
| Recommendation — Validate file paths and constrain file handling to approved directories. Log anomalous path input and review file-access errors for exploitation evidence. | ||
| CIS Controls v8 | CIS-16 — Application Software Security | Rails traversal is a web application weakness that belongs in secure application control coverage. |
| Recommendation — Harden application input handling and remediate web flaws through secure development controls. | ||
| NIST SP 800-53 Rev 5 | SI-10 — Information Input Validation | Traversal depends on unsafe handling of user-controlled path input. |
| AU-6 — Audit Record Review, Analysis, and Reporting | Detection and post-exploitation review rely on log analysis and correlation. | |
| Recommendation — Validate and sanitize path input before the application resolves a file location. Review logs for traversal attempts and follow-on file-access anomalies. | ||
Practitioner Guidance
Why practitioners should care: Treat this class of issue as both an application bug and a secrets-exposure event. A traversal fix is necessary, but it is not sufficient if the application has already revealed configuration or identity material that can be reused.
What to watch for: Look for suspicious path inputs, unexpected file reads, and any sign that secret-bearing files were accessible during the vulnerable period. If exploitation is suspected, review adjacent systems for credential reuse and secondary access paths.
Related resources from NHI Mgmt Group
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Reviewed and updated by the NHIMG editorial team on October 17, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org