Memory corruption via packed-array count overflow
Published Dec 27, 2025 · Updated Dec 27, 2025
Heap buffer overflow in PHP allows remote attackers to corrupt memory or crash a PHP process through application-controlled packed arrays. The packed-array optimization in array_merge() adds zend_hash_num_elements() results to a precomputed count without rejecting integer overflow before allocation and element copying. Reachability requires application code to pass enough attacker-influenced arrays to exceed HT_MAX_SIZE or the 32-bit limit in affected PHP 8.1 through 8.5 branches.
Summary
What happened
Heap buffer overflow in PHP allows remote attackers to corrupt memory or crash a PHP process through application-controlled packed arrays. The packed-array optimization in array_merge() adds zend_hash_num_elements() results to a precomputed count without rejecting integer overflow before allocation and element copying. Reachability requires application code to pass enough attacker-influenced arrays to exceed HT_MAX_SIZE or the 32-bit limit in affected PHP 8.1 through 8.5 branches.
The record
- CVE
- CVE-2025-14178
- Published
- Dec 27, 2025
- Updated
- Dec 27, 2025
- Vendor
- The PHP Group
- Product
- PHP
- Classifications
- CWE-787, CWE-190, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 27, 2025CVE publishedPublication date reported by the CVE source.
- Dec 27, 2025Record 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=8.1.* <8.1.34
- Affected versionversion=8.2.* <8.2.30
- Affected versionversion=8.3.* <8.3.29
- Affected versionversion=8.4.* <8.4.16
- Affected versionversion=8.5.* <8.5.1
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
- GHSA-h96m-rvf9-jgm2 heap-overflow triggerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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