Is CVE-2026-82531 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-82531 being exploited in the wild.

How severe is CVE-2026-82531?

High severity, with a CVSS score of 8.1, published 6 October 2026.

Which products and versions are affected?

Smarty before 4.5.8 and 5.x before 5.8.5.

Is there a fix for CVE-2026-82531?

Yes: fixed in Smarty 4.5.8, 5.8.5. Until then: Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-82531 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-82531?

Check whether you run Smarty at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-82531: Smarty code injection in template inheritance via nocache hash

CVE-2026-82531 · Severity: high · CVSS 8.1 · Published 2026-10-06

Smarty is a PHP template engine used to render dynamic web content. A vulnerability in template inheritance allows attackers to inject arbitrary PHP code into cached template files through forged nocache markers in assigned data. When a template uses the extends: path for inheritance, an attacker can poison the cached PHP file to execute code remotely when the template is next loaded.

Technologies: Smarty. Vendors: Smarty.

Quick answers

Is CVE-2026-82531 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-82531 being exploited in the wild.
How severe is CVE-2026-82531?: High severity, with a CVSS score of 8.1, published 6 October 2026.
Which products and versions are affected?: Smarty before 4.5.8 and 5.x before 5.8.5.
Is there a fix for CVE-2026-82531?: Yes: fixed in Smarty 4.5.8, 5.8.5. Until then: <UNKNOWN> Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-82531 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-82531?: Check whether you run Smarty at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: Smarty 4.5.8, 5.8.5

Technical details

The vulnerability is a code injection (CWE-94) in Smarty's template inheritance via extends: path. When a template is rendered through extends:/inheritance, the top-level unifunc's nocache_hash is never restored and remains null, causing the cache-split regex to produce an empty alternative "(realhash|)" in Smarty_Internal_Runtime_UpdateCache. This allows attacker-controlled template output to forge a /*%%SmartyNocache:%%*/ marker that gets copied verbatim into the generated PHP cache file as raw PHP code, executing on next include(). The attack requires template inheritance and assignment of attacker-controlled data.

Affected products

Smarty Smarty before 4.5.8 and 5.x before 5.8.5

Timeline

2026-10-06: disclosed
2026-10-04: patched

References

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