Remote code execution via shutdown reference counting
Published Apr 4, 2025 · Updated Feb 26, 2026
Use-after-free in PHP 8.3 before 8.3.19 and 8.4 before 8.4.5 allows remote attackers to execute code via crafted script inputs. An exception handler frees live variables through cleanup_live_vars, but php_request_shutdown later reads and decrements their invalid reference counts, modifying Zend allocator metadata. Exploitation requires application code using the affected __set or ??= sequence, an exception during assignment, and attacker control sufficient to shape the freed heap memory.
Summary
What happened
Use-after-free in PHP 8.3 before 8.3.19 and 8.4 before 8.4.5 allows remote attackers to execute code via crafted script inputs. An exception handler frees live variables through cleanup_live_vars, but php_request_shutdown later reads and decrements their invalid reference counts, modifying Zend allocator metadata. Exploitation requires application code using the affected __set or ??= sequence, an exception during assignment, and attacker control sufficient to shape the freed heap memory.
The record
- CVE
- CVE-2024-11235
- Published
- Apr 4, 2025
- Updated
- Feb 26, 2026
- Vendor
- The PHP Group
- Product
- PHP
- Classifications
- CWE-416, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 4, 2025CVE publishedPublication date reported by the CVE source.
- Feb 26, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=8.3.* <8.3.19
- Affected versionversion=8.4.* <8.4.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- PHP CLI use-after-free proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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