Use After Free in PHP
CVE-2026-109618
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).
Vulnerability class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/php/php-src/security/advisories/GHSA-w8hw-w9fx-j79w (vendor-advisory, Mitigation, Vendor Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Third Party Advisory)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2026-109618?
- CVE-2026-109618 is a critical-severity vulnerability in PHP, classified under Use After Free. CVSS score: 9.8/10. Published 2026-10-21.
- How severe is CVE-2026-109618?
- Critical severity. CVSS v3 base score is 9.8 out of 10.