CVE-2021-26120Public exploit

PHP code execution via unchecked function names

Published Feb 22, 2021 · Updated Aug 3, 2024

Code injection in Smarty before 3.1.39 allows template authors to execute arbitrary PHP through a malicious template function name. Smarty_Internal_Compile_Function accepted the name attribute without validating its characters, then incorporated the value into generated PHP code. Exploitation requires control of Smarty template source; injected PHP runs with the privileges of the process compiling or rendering the template.

CVSS severity9.8
Critical
EPSS probability82.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in Smarty before 3.1.39 allows template authors to execute arbitrary PHP through a malicious template function name. Smarty_Internal_Compile_Function accepted the name attribute without validating its characters, then incorporated the value into generated PHP code. Exploitation requires control of Smarty template source; injected PHP runs with the privileges of the process compiling or rendering the template.

The record

CVE
CVE-2021-26120
Published
Feb 22, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-94, T1059
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Feb 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1059Command and Scripting Interpreter

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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