Code Injection in phalcon/cphalcon (CVE-2026-59989)
Summary
Code injection in phalcon/cphalcon (CVE-2026-59989). Risk of unauthorized operations or information disclosure. Exploitable via join. Mitigation: upgrade to 5.16.0 or later.
Original description
The description as published by the source.
Summary
The Volt template compiler in Phalcon generates the PHP for the join filter by string-concatenating the filter's raw template-literal argument bytes with no escaping. The separator literal is dropped verbatim between two single quotes the compiler emits, and the piped array argument is emitted completely bare. A Volt template whose join arguments are attacker-influenced can therefore break out of the generated join('…') call and inject arbitrary PHP into the compiled template. Volt writes that compiled template to a cache file and require()s it at render time, so the injected PHP executes i.e. compile-time PHP code injection (server-side template injection -> remote code execution) for any application that compiles attacker-controlled Volt source.
Details
Root cause
phalcon/Mvc/View/Engine/Volt/Compiler.zep:2544-2546:
case "join":
return "join('" . funcArguments[1]["expr"]["value"]
. "', " . funcArguments[0]["expr"]["value"] . ")";
funcArguments[1]["expr"]["value"] (the separator) and funcArguments[0]["expr"]["value"] (the piped array) are the raw values of the parsed template tokens. Unlike every other expression in the compiler, they are not routed through expression() and receive no escaping: the separator value is spliced verbatim inside the join(' … ' quotes with no neutralisation of ', and the array value is emitted with no quoting at all. Volt's scanner stores string-literal bytes verb…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-59989 has been found in phalcon/cphalcon.
Attackers can target a specific entry point like join over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade phalcon/cphalcon to 5.16.0 or later.
If unsure, ask your IT team or search "phalcon/cphalcon CVE-2026-59989" on the vendor's site.
CVE-2026-59989 (phalcon/cphalcon) — CWE-94
Attack surface: join / require
Patched: 5.16.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Arbitrary code execution (CWE-94) exists in phalcon/cphalcon. Attackers reach the vulnerable code path via join.
Check the vendor advisory for the affected versions of phalcon/cphalcon. Attack surface: join / require.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 5.16.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'phalcon/cphalcon' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'phalcon/cphalcon' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
phalcon/cphalconを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade phalcon/cphalcon to 5.16.0ステージング環境で 5.16.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。