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CVE-2015-6834

CRITICAL severity · CVSS 9.8
9.8CVSS CRITICAL

Summary

Multiple use-after-free vulnerabilities in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13 allow remote attackers to execute arbitrary code via vectors related to (1) the Serializable interface, (2) the SplObjectStorage class, and (3) the SplDoublyLinkedList class, which are mishandled during unserialization.

Impact & exploitability

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)35%

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products we track (1)

PHP

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Last checked: Wed, 10 Jun 2026 22:18:30 UTC