PHP Use After Free Vulnerability - CVE-2026-6722

In PHP versions 8.2. before 8.2.31 8.3. before 8.3.31 8.4. before 8.4.21 and 8.5. before 8.5.6 the SOAP extension39s object deduplication mechanism stores pointers to PHP objects in a global mapwithout incrementing their reference counts. When an apache:Map node contains duplicate keys processing the second entry overwrites the first in the temporary result map freeing the original PHP object while its stale pointer remains in the map. A subsequent href reference to the freed node can copy the dangling pointer into the result. As PHP string allocations can reclaim the freed memory region an attacker with control over the SOAP request body can exploit this use-after-free to achieve remote code execution.