Summary
October CMS: Incomplete Scheme Validation in Image Resizer
The image resizer classified external sources by testing whether the source string began with the substring http, and the string-source branch in ResizeImageItem::fromObject() accepted any value containing :// as a URL. As a result, non-http(s) PHP stream wrappers such as phar://, file:// and ftp:// could be stored in the resizer cache and later passed to the underlying image library. On a phar:// path this can lead to metadata deserialization during subsequent file operations.
Exploitation requires an existing template-authoring or backend-configuration primitive that passes untrusted input into the |resize Twig filter (or the ResizeImages::resize() API). The /resize/{file} route itself is a lookup against a cache entry that was previously written by trusted server-side code, and an unauthenticated visitor cannot cause an arbitrary source path to be written into that cache. In October's trust model the Publisher and Developer backend roles that can author templates are already trusted with template code execution, so this is a defense-in-depth hardening rather than an unauthenticated network-to-RCE path.
Workarounds
If upgrading immediately is not possible:
- Audit template code and backend widget configuration for uses of the
|resizefilter (or directResizeImages::resize()calls) that accept untrusted string input, and validate the scheme ishttp/httpsbefore passing it in
References
- Reported by 0xGenesi
Impact
- On installations where a template author has piped untrusted input into
|resizewithout validation, aphar://source could reach the resizer and trigger metadata deserialization - No exposure on default templates or on installations where
|resizeis only applied to trusted values (uploaded file models, theme assets, static URLs) - Hardening; not exploitable from the network without a pre-existing injection primitive on the calling code
The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.
GHSA-2XMM-M4WV-3FJH has a CVSS score of 3.9 (Low). The vector is network-reachable, high privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.3.5); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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The vulnerability has been patched in v4.3.5.
Frequently Asked Questions
- What is GHSA-2XMM-M4WV-3FJH? GHSA-2XMM-M4WV-3FJH is a low-severity improper input validation vulnerability in october/october (composer), affecting versions >= 4.3.0, < 4.3.4. It is fixed in 4.3.5. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
- How severe is GHSA-2XMM-M4WV-3FJH? GHSA-2XMM-M4WV-3FJH has a CVSS score of 3.9 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of october/october are affected by GHSA-2XMM-M4WV-3FJH? october/october (composer) versions >= 4.3.0, < 4.3.4 is affected.
- Is there a fix for GHSA-2XMM-M4WV-3FJH? Yes. GHSA-2XMM-M4WV-3FJH is fixed in 4.3.5. Upgrade to this version or later.
- Is GHSA-2XMM-M4WV-3FJH exploitable, and should I be worried? Whether GHSA-2XMM-M4WV-3FJH is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-2XMM-M4WV-3FJH is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-2XMM-M4WV-3FJH? Upgrade
october/octoberto 4.3.5 or later.