Heap Overflow Vulnerability in Linux Kernel SMB Client
CVE-2026-97555
Key Information:
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What is CVE-2026-97555?
The Linux kernel has a vulnerability in the SMB client, which can cause a heap overflow during the rewriting of discretionary access control lists (DACLs). This occurs when the size of SID (Security Identifier) replacement exceeds the allocated buffer size, particularly when transitioning from short to long SIDs. The flaw manifests during the allocation of buffers based on reported DACL lengths, potentially leading to memory corruption. The vulnerability has been rectified by implementing a safer allocation method that considers the maximum possible size for each access control entry (ACE). This ensures that sufficient memory is reserved to prevent overflow during SID replacements, thereby enhancing the robustness of access control in network file sharing.
Affected Version(s)
Linux bc3e9dd9d104ca1b75644eab87b38ce8a924aef4
Linux bc3e9dd9d104ca1b75644eab87b38ce8a924aef4
Linux bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 < 7fa84c9ca690643f429ae2709584a47e74b572c9
Exploit Proof of Concept (PoC)
PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.