CVE-2026-109618
Description
A flaw was found in PHP's memory limit handling during request parsing. PHP records certain state as ready for use before all required memory allocations complete. If an allocation fails due to memory exhaustion, the incomplete state is not rolled back. Subsequent cleanup operations treat the uninitialized memory as valid, leading to memory corruption. An unauthenticated attacker can exploit this via crafted HTTP requests to achieve remote code execution against mod_php with default configuration, and against FPM through application-stage paths.
Security Bulletin
Statement
Rated Important. An unauthenticated remote attacker could corrupt engine memory and potentially execute arbitrary code, but reliable exploitation requires precise heap manipulation and timing. Standard Red Hat Enterprise Linux deployments use PHP-FPM rather than mod_php. PHP-FPM workers exit on early initialization failures before reaching the corrupted structures, so remote code execution is difficult in practice and typically requires non-default behavior such as parsing a second request body during script execution.
Mitigation
See the security bulletin for a detailed mitigation procedure.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.1 | 9.8 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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