smarty/smarty security advisory

CVE-2026-62993: Smarty: SSRF via redirect bypass of trusted_uri using {fetch}

CVE-2026-62993 is a medium-severity SSRF vulnerability in the PHP package smarty/smarty (CVSS 6.9), published 31 August 2026. It is fixed in 4.5.7 and 5.8.2, one per release line; earlier versions on each line are affected. It can be exploited without an account.

medium 6.9 published 2026-08-31 · updated 2026-09-08

Affected versions: < 4.5.7
>= 5.0.0, < 5.8.2
Fixed in: 4.5.7, 5.8.2
Newest release: 5.8.5
Severity: Medium · CVSS 6.9
Type: Server-side request forgery (SSRF)
CWE-918
Exploited in the wild: Not on the CISA KEV list
checked 2026-11-04

Is your smarty/smarty version affected?

Run composer show smarty/smarty in your project, then enter the version. We check it against this and every other known smarty/smarty advisory.

Who can exploit CVE-2026-62993

Access: No account. Anyone who can send a request to an app that uses the affected code.
Conditions: It only works under specific conditions the attacker does not fully control (CVSS rates the attack as high complexity).

CVSS vector (scored by GitHub): CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

Your app is only exposed if it uses the affected part of smarty/smarty. The advisory below says which part that is. If you are not sure, upgrade anyway: it costs less than finding out.

How to fix CVE-2026-62993 in smarty/smarty

Find the installed version: composer show smarty/smarty. If you never required it yourself, composer why smarty/smarty shows which package pulls it in.
Update it: composer update smarty/smarty --with-all-dependencies. You need the fixed version for your release line (4.5.7 and 5.8.2).
If Composer will not go that high, your composer.json constraint is holding it back. Widen it (for example "smarty/smarty": "^5.8.2" if you can take that version), or upgrade the package that requires it.
Run composer audit. It reads the same advisory data and should no longer list CVE-2026-62993.
Commit composer.lock and deploy it. On the server, run composer install --no-dev from the lock file, not composer update.

If you cannot upgrade yet

General hardening for SSRF issues while the upgrade waits. None of it replaces the fix.

Block outbound requests from the app server to private ranges and cloud metadata (169.254.169.254) at the firewall.
Do not pass user-supplied URLs to the affected feature.
If your app does not use the affected feature, note that in your audit, but still plan the upgrade.

The CVE-2026-62993 advisory

Smarty is a template engine for PHP, facilitating the separation of presentation (HTML/CSS) from application logic. Prior to 4.5.7 and 5.8.2, depending on the release line, Smarty's {fetch} handling in libs/plugins/function.fetch.php and src/FunctionHandler/Fetch.php used Security::isTrustedUri() to validate only the initial remote URL against trusted_uri when a security policy was active. For resources handled by file_get_contents(), including HTTPS URLs, PHP followed HTTP redirects by default. An attacker who could supply or influence a fetch target and had an open redirect on a trusted host could redirect the request to an attacker-chosen internal endpoint, bypass the trusted_uri allowlist, and perform server-side request forgery. This issue is fixed in versions 4.5.7 and 5.8.2.

Description from the CVE record, published by GitHub (the CVE Numbering Authority), via the NVD entry for CVE-2026-62993. Advisory title: “Smarty: SSRF via redirect bypass of trusted_uri using {fetch}”.

References

GitHub advisory GHSA-cq55-c7wv-pxmq github.com
Fix commit 31e06fc github.com
Fix commit a1ccdb0 github.com
Pull request #1194 github.com
Release v4.5.7 github.com
Release v5.8.2 github.com

Other smarty/smarty advisories

medium CVE-2026-62996: Smarty Security stream restriction bypass through stream: resource 2026-08-07
medium CVE-2026-62992: Smarty: Symlink path traversal out of trusted directories 2026-08-07
high CVE-2024-35226: Smarty vulnerable to PHP Code Injection by malicious attribute in extends-tag 2024-05-29
high CVE-2023-28447: Cross site scripting vulnerability in Javascript escaping 2023-03-28
medium CVE-2018-25047: Smarty_function_mailto - JavaScript injection in eval function 2022-09-14
high CVE-2022-29221: PHP Code Injection by malicious block or filename 2022-05-17

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Where this data comes from

Affected and fixed versions: the Packagist security advisories API (GitHub Advisory Database and FriendsOfPHP), the same data composer audit uses. Synced 2026-11-03.
Description, score, weakness and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
Exploited-in-the-wild status: the CISA Known Exploited Vulnerabilities catalog, checked 2026-11-04.
Compiled by Daniel Lasek at Laskyr from the sources above. The summary, “who can exploit it”, “how to fix it” and hardening sections are our plain-English reading of the record and are generated from it. The quoted description is the record's own text. Spot an error? Tell us.