9.2
CRITICAL CVSS 4.0
CVE-2026-59989
Phalcon Volt compiler `join` filter compile-time PHP code injection (SSTI lead to RCE)
Description

Phalcon is a high-performance, full-stack PHP framework. In 5.15.0 and earlier, resolveFilter in phalcon/Mvc/View/Engine/Volt/Compiler.zep builds the join filter by inserting the raw separator and array token values into generated PHP without passing them through expression(). An attacker who can influence Volt template source can place quote-breaking content in a join argument, inject PHP into the compiled cache file, and execute it when Phalcon\Mvc\View\Engine\Volt::render() loads the template. This issue is fixed in version 5.16.0.

INFO

Published Date :

Aug. 21, 2026, 9:17 p.m.

Last Modified :

Aug. 21, 2026, 9:17 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-59989 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 CRITICAL [email protected]
Solution
Update Phalcon to version 5.16.0 to fix a template injection vulnerability in Volt compiler.
  • Update Phalcon to version 5.16.0 or later.
  • Ensure template sources are properly validated.
  • Review compiled cache files for suspicious code.
References to Advisories, Solutions, and Tools
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-59989 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-59989 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-59989 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-59989 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Aug. 21, 2026

    Action Type Old Value New Value
    Added Affected [{'vendor': 'phalcon', 'product': 'cphalcon', 'versions': [{'status': 'affected', 'version': '< 5.16.0'}]}]
    Added Description Phalcon is a high-performance, full-stack PHP framework. In 5.15.0 and earlier, resolveFilter in phalcon/Mvc/View/Engine/Volt/Compiler.zep builds the join filter by inserting the raw separator and array token values into generated PHP without passing them through expression(). An attacker who can influence Volt template source can place quote-breaking content in a join argument, inject PHP into the compiled cache file, and execute it when Phalcon\Mvc\View\Engine\Volt::render() loads the template. This issue is fixed in version 5.16.0.
    Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CWE CWE-94
    Added CWE CWE-1336
    Added Reference https://github.com/phalcon/cphalcon/commit/e434061be3b7161930476c1368c868badc71e1bd
    Added Reference https://github.com/phalcon/cphalcon/pull/17217
    Added Reference https://github.com/phalcon/cphalcon/releases/tag/v5.16.0
    Added Reference https://github.com/phalcon/cphalcon/security/advisories/GHSA-hrwp-4hh9-c8r8
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.