Security Digest · Vulnerability record
CVE-2026-109618: RCE via OOM corruption
PHP uses longjmp() for out-of-memory (OOM) errors to exit the current context and abort handling of the request.
CVSS 9.2 Critical Act now
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Act now. PHP2Shell: Critical Unauthenticated RCE in PHP — If PHP answers HTTP requests anywhere you run it, patch or apply a vendor fix today; this is pre-application, unauthenticated, and attack traffic started before the patch shipped.
What it is
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).
Weakness type: CWE-416, CWE-755, CWE-824, CWE-1325, CWE-1419.
Product: PHP Group PHP · Assigned by: php · Published: 2026-10-21
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| PHP Group | PHP | 8.2.* < 8.2.35, 8.3.* < 8.3.36, 8.4.* < 8.4.27, 8.5.* < 8.5.12 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| php | 4.0 | 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 |
- Attack vector: network (remotely reachable)
- Attack complexity: high (needs special conditions)
- Attack requirements: present (depends on deployment conditions)
- Privileges required: none (no login)
- User interaction: none
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
Timeline
- — CVE record last updated
- — CVE record published by php
- — erroneo.us brief: PHP2Shell: Critical Unauthenticated RCE in PHP
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- github.com github.com
Vulnerability records
- CVE.org record CVE-2026-109618 cve.org
- NVD entry CVE-2026-109618 nvd.nist.gov
Other references from the CVE record and advisory
- wiz.io wiz.io
- openwall.com openwall.com