CVE-2026-109618
PHP Memory Corruption Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 29 October 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
PHP uses longjmp() for out-of-memory (OOM) errors to exit the current context and abort handling of the request. Some contexts may not properly account for this scenario and leave request memory in an uninitialized state before performing an allocation. The subsequent request cleanup procedure may read or branch on this memory. Multiple OOM strategies can consistently trigger this condition and lead to remote code execution (RCE).
- CVSS 4.0
- 9.2 CRITICALCVSS:4.0/AV:N/AC:H/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/M
- EPSS
- 99.98% probability · 100th percentile
- Public exploits
- 1 in Exploit-DB · verified · first 22 October 2026
- CISA KEV
- Listed 26 October 2026 · due 29 October 2026
- Weakness
- CWE-416, CWE-755, CWE-824, CWE-1325
- Affected
- php/php · siemens/ruggedcom ape1808 firmware · paloaltonetworks/pan-os · paloaltonetworks/panorama virtual appliance
- Source
- security@php.net
EPSS moved from 5.3% on 22 October 2026 to 100.0% on 26 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
CISA notes
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://www.php.net/ ; https://www.cisa.gov/news-events/alerts/2026/10/21/critical-vulnerabilities-php-require-immediate-patching ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-109618
Public exploits (1)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
References
- https://github.com/php/php-src/security/advisories/GHSA-w8hw-w9fx-j79wMitigation, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2026/10/21/6Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/10/23/5Mailing List, Third Party Advisory
- https://arcticwolf.com/resources/blog/php2shell-critical-php-vulnerabilities-enable-unauthenticated-remote-code-execution/Third Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-566512.htmlThird Party Advisory
- https://php2shell.delftintellab.comThird Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-109618US Government Resource
- https://www.wiz.io/blog/php2shell-php-rceThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.