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- CVE-2026-109618 and CVE-2026-109619, collectively known as php2shell, represent critical remote code execution vulnerabilities in the PHP runtime.
- These flaws originate deep within the core C source code of the PHP interpreter rather than in user-space application scripts.
- Both mod_php and PHP-FPM deployment modes are affected, exposing standard Apache and Nginx web server configurations.
- The vulnerability triggers during the handling of multipart form data and complex request parsing routines.
- Out-of-memory errors handled via longjmp() leave internal memory structures uninitialized and vulnerable.
- An unauthenticated attacker can exploit this uninitialized memory state through malformed HTTP requests.
- Successful exploitation corrupts internal interpreter pointers, allowing arbitrary command execution on the host server.
- Because the attack vector bypasses application code, secure CMS installations and frameworks remain entirely vulnerable.
- Threat actors have successfully chained these bugs into pre-authentication exploit tools for immediate system takeover.
- Active exploitation attempts in the wild have been documented immediately following public advisory releases.
- Virtually all PHP versions from PHP 5 through PHP 8.4 contain the underlying historical design flaw.
- Legacy versions like PHP 5.x, 7.x, 8.0, and 8.1 receive no official patches from the PHP volunteer group.
- Organizations running unsupported versions face immediate risks and must seek vendor backports or immediate upgrades.
- Official security releases provide fixes across supported branches, including PHP 8.5.12, 8.4.27, 8.3.36, and 8.2.35.
- Automated auditing utilities like php2shell-repo-audit assist teams in inventorying declared PHP versions across repositories.
- Temporary mitigations include disabling multipart form handling or applying advanced WAF transaction rules.
- WAF rules inspect both request patterns and origin responses to block potential exploitation attempts.
- However, WAF rules serve only as a temporary stopgap and do not replace the necessity of patching the runtime.
- Defenders should monitor PHP child processes for anomalous shell spawns, such as unexpected executions of bash or curl.
- Incident response plans must include server isolation, log preservation, and forensic investigation for webshells.
- Compromised environments require full credential rotation for databases, SSH keys, and administrative panels.
- Rebuilding compromised servers from trusted clean images is recommended over simple file deletion.
- Backup integrity verification ensures that disaster recovery procedures can be executed reliably.
- Prioritizing internet-facing assets during the patch cycle minimizes the window of vulnerability exposure.
- Collaboration across security communities helps track evolving exploit variants and patch availability.
- Continuous monitoring of error logs and memory limit exceptions provides early indicators of compromise.
- Strict network segmentation can limit lateral movement if a backend PHP worker is compromised.
- Ultimately, maintaining strict asset visibility and rapid patch management remains the primary defense against interpreter-level RCE.
DailyCVE Form:
Platform: PHP engine
Version: PHP 5-8.4
Vulnerability: Remote execution
Severity: Critical impact
date: October 21
Prediction: Patched today
What Undercode Say:
npx [email protected] path/to/repo npx [email protected] --org your-org --markdown > php2shell.md grep -rnE "FROM +php:" .
{
"name": "php2shell-repo-audit",
"version": "0.1.0",
"dependencies": {}
}
Exploit: (Educational Purposes!)
An unauthenticated attacker sends a malformed HTTP request with specially crafted multipart form data designed to trigger an out-of-memory error condition. During the resulting longjmp() exception handling, the PHP interpreter leaves internal memory buffers uninitialized. The exploit payload leverages this memory exposure to overwrite function pointers within the C runtime. When the interpreter attempts to service subsequent operations, execution control is hijacked, redirecting CPU instructions to run shell commands on the underlying operating system.
Protection: from this CVE
Update PHP immediately to official fixed versions (8.5.12, 8.4.27, 8.3.36, or 8.2.35).
Deploy WAF transaction rules to inspect and block malicious multipart requests and abnormal origin responses.
Isolate end-of-life PHP environments (5.x, 7.x, 8.0, 8.1) behind secure VPNs or take them offline.
Monitor PHP child processes for unauthorized shell execution or download tool invocations.
Audit code repositories and Dockerfiles using automated tools like php2shell-repo-audit.
Impact:
Complete remote code execution and full system takeover of vulnerable web servers.
Unauthenticated pre-auth compromise affecting millions of internet-facing PHP applications and CMS platforms.
Severe data theft, database extraction, deployment of persistent webshells, and lateral network movement.
Widespread disruption across enterprise infrastructure, hosting providers, and legacy software stacks.
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Sources:
Reported By: github.com
Extra Source Hub:
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