Summary
Smarty: SSRF via redirect bypass of trusted_uri using {fetch}
When a Security policy is active, {fetch} validates the requested remote URL against the trusted_uri allowlist via Security::isTrustedUri(). For non-http:// schemes (e.g. https://) the resource was then read with file_get_contents(), which follows HTTP redirects by default. Because isTrustedUri() only validates the initial URL, an open redirect on an otherwise-trusted host could be used to redirect the request to a non-trusted, internal target, bypassing the trusted_uri policy.
Workarounds
Avoid fetching remote resources from within templates under untrusted control; ensure hosts listed in trusted_uri do not expose open redirects.
Impact
An attacker who can supply a fetch target (or influence one) and who has an open redirect available on a trusted host can cause the server to issue requests to attacker-chosen internal endpoints, defeating the trusted_uri allowlist (server-side request forgery).
Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.
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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Fixed in 5.8.2. When a security policy is active, {fetch} now passes a stream context that disables redirect following (follow_location => 0, max_redirects => 1) to file_get_contents() for remote resources. Behavior is unchanged when no security policy is set, since there is no trusted_uri to bypass.
Frequently Asked Questions
- What is CVE-2026-62993? CVE-2026-62993 is a medium-severity server-side request forgery (SSRF) vulnerability in smarty/smarty (composer), affecting versions >= 5.0.0, < 5.8.2. It is fixed in 5.8.2, 4.5.7. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
- Which versions of smarty/smarty are affected by CVE-2026-62993? smarty/smarty (composer) versions >= 5.0.0, < 5.8.2 is affected.
- Is there a fix for CVE-2026-62993? Yes. CVE-2026-62993 is fixed in 5.8.2, 4.5.7. Upgrade to this version or later.
- Is CVE-2026-62993 exploitable, and should I be worried? Whether CVE-2026-62993 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 CVE-2026-62993 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 CVE-2026-62993?
- Upgrade
smarty/smartyto 5.8.2 or later - Upgrade
smarty/smartyto 4.5.7 or later
- Upgrade