{"id":87046,"date":"2026-06-05T06:19:56","date_gmt":"2026-06-05T06:19:56","guid":{"rendered":""},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-30T00:00:00","slug":"cve-2025-57632-buffer-overflow-vulnerability-in-libsmb2-6-2","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-57632-buffer-overflow-vulnerability-in-libsmb2-6-2\/","title":{"rendered":"CVE-2025-57632: Buffer Overflow Vulnerability in libsmb2 6.2+<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

This report details the buffer overflow vulnerability in libsmb2 6.2+ identified as CVE-2025-57632. The vulnerability impacts systems running this particular software version, presenting a significant threat as it can potentially allow an attacker to execute arbitrary code, leading to system compromise or data leakage.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-57632
\nSeverity: High (7.5 CVSS)
\nAttack Vector: Network
\nPrivileges Required: None
\nUser Interaction: None
\nImpact: System compromise, data leakage, memory corruption, and crashes<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

libsmb2 | 6.2+<\/p>\n

How the Exploit Works<\/strong><\/p>\n

The vulnerability stems from improper handling and validation of SMB2 chained PDUs inside libsmb2. When processing these chained PDUs, the software repeatedly calls the function smb2_add_iovector() to append to a fixed-size iovec array without checking the upper bound, v->niov, which is capped at 256 (SMB2_MAX_VECTORS).
\nAn attacker can exploit this vulnerability by crafting responses with numerous chained PDUs, causing an overflow of v->niov. This results in heap out-of-bounds writes, which lead to memory corruption, system crashes, and potentially arbitrary code execution. Furthermore, the SMB2_OPLOCK_BREAK path bypasses message ID validation, making it easier for an attacker to exploit this vulnerability.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

Below is a conceptual example of how an attacker might exploit this vulnerability. This pseudocode represents a malicious SMB2 response with an abnormal number of chained PDUs:<\/p>\n

SMB2_Header {\nProtocolId: SMB2,\nMessageId: 0x1,\n...\n}\nSMB2_Chained_PDU {\nNextCommand: 0x1,\n...\n}\n...\nSMB2_Chained_PDU {\nNextCommand: 0x100, \/\/ Exceeds SMB2_MAX_VECTORS\n...\n}<\/code><\/pre>\n
This code results in an overflow of the v->niov variable, leading to memory corruption and potential arbitrary code execution. By sending a large number of these responses, an attacker can crash the system or even take control of it.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview This report details the buffer overflow vulnerability in libsmb2 6.2+ identified as CVE-2025-57632. The vulnerability impacts systems running this particular software version, presenting a significant threat as it can potentially allow an attacker to execute arbitrary code, leading to system compromise or data leakage. Vulnerability Summary CVE ID: CVE-2025-57632 Severity: High (7.5 CVSS) Attack […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[],"tags":[],"vendor":[],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-87046","post","type-post","status-publish","format-standard","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t