Phalcon Volt compiler `join` filter compile-time PHP code injection (SSTI lead to RCE) (CVE-2026-59989) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-59989

Phalcon Volt compiler `join` filter compile-time PHP code injection (SSTI lead to RCE)

Answer in brief

CVE-2026-59989 records a Unknown severity vulnerability in Phalcon Volt compiler `join` filter compile-time PHP code injection (SSTI lead to RCE). The current sources do not mark it as known exploited. The current feed maps phalcon/cphalcon (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 21, 2026Updated Aug 21, 2026Source checked Aug 21, 2026First seen by HOL Aug 21, 2026Material review Aug 21, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps phalcon/cphalcon (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
phalcon/cphalcongeneric	< 5.16.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for phalcon/cphalcon.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Aug 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 21, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.