Known exploited vulnerability · CISA KEV

CVE-2026-109618: PHP Memory Corruption Vulnerability

PHP contains an out-of-memory corruption vulnerability that allows for unauthenticated remote code execution.

CVE-2026-109618

Exploited in the wild. Fix this first.

CISA added it to the Known Exploited Vulnerabilities catalog on 2026-10-26: attackers are using it right now.

CISA KEV: Listed; Added 2026-10-26 · federal fix-by 2026-10-29
EPSS (30 days): over 99.9%; Higher than 99.9% of CVEs · 2026-11-01
CVSS v4.0: 9.2 Critical; CVSS: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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

What CISA says

PHP Memory Corruption Vulnerability

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.

NVD description · published 2026-10-21

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).

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How to check if you are exposed to CVE-2026-109618

Find every PHP Group PHP system you or your clients run, including ones exposed to the internet. Those come first: CISA only lists flaws attackers are already using.
Compare each version with the fixed versions in the vendor advisory below. Where no fix exists yet, apply the vendor’s mitigation or take the system off the internet.
Run a credentialed vulnerability scan to catch the systems you missed, then check that the next scan no longer reports CVE-2026-109618.

US federal agencies had to fix this by 2026-10-29. Everyone else should treat that deadline as a guide: if it has passed, this is overdue.

Affected versions

Versions the National Vulnerability Database lists as vulnerable to CVE-2026-109618. Check the vendor advisory for the exact fixed builds before you sign anything off.

Product	Vulnerable versions
PHP	from 7.3.0 before 8.2.35; from 8.3.0 before 8.3.36; from 8.4.0 before 8.4.27; from 8.5.0 before 8.5.12
Siemens Ruggedcom Ape1808 Firmware	all versions
Paloaltonetworks Pan-Os	from 10.2.0 before 10.2.7; 10.2.7; 10.2.7-h1; 10.2.7-h10; 10.2.7-h11; 10.2.7-h12 and 286 more
Paloaltonetworks Panorama Virtual Appliance	all versions

Timeline

2026-10-21 · Published in the National Vulnerability Database
2026-10-26 · Added to CISA's Known Exploited Vulnerabilities catalog, 5 days after it was published
2026-10-29 · Fix-by date for US federal agencies, passed 3 days ago

Vendor advisories and fixes

Weakness type

More exploited PHP Group vulnerabilities

CISA lists 3 exploited PHP Group vulnerabilities. The closest matches:

Keep going

Sources: CISA Known Exploited Vulnerabilities catalog (version 2026.10.30); EPSS data from FIRST.org; CVSS and descriptions from the NIST National Vulnerability Database. Checked 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.