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CVE-2026-76642— util-linux libmount Privilege Escalation via Failed Mount Helper

Quick assessment

Affected
util-linux util-linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

util-linux是util-linux组织开源的一套操作系统基础工具集。 util-linux 2.41.5及之前版本和2.42.2及之前版本存在异常处理不当漏洞，该漏洞源于在运行挂载后钩子前未检查挂载辅助程序退出状态，导致低权限用户可在挂载辅助程序失败后利用X-mount.idmap或X-mount.owner钩子，克隆具有继承suid位的文件系统或修改目标inode权限，从而实现权限提升。

CVSS 7.8 · High EPSS 0.18% · P7

Affected Version Matrix 2

VendorProduct Version RangeStatus
util-linux util-linux 2.39< 2.41.6 affected
2.42< 2.42.3 affected
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I. Basic Information for CVE-2026-76642

Vulnerability Information
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Vulnerability Title
util-linux libmount Privilege Escalation via Failed Mount Helper
Source: CVE Program / CVE List V5
Vulnerability Description
util-linux versions through 2.41.5 and 2.42.2 fail to check mount helper exit status before running post-mount hooks, allowing unprivileged users to execute privileged operations on pre-existing filesystems. Attackers can exploit X-mount.idmap or X-mount.owner hooks to clone filesystems with inherited suid bits or modify target inode permissions after a helper fails, achieving privilege escalation.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
未有动作错误条件的检测
Source: CVE Program / CVE List V5
Vulnerability Title
util-linux 异常处理不当漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
util-linux是util-linux组织开源的一套操作系统基础工具集。 util-linux 2.41.5及之前版本和2.42.2及之前版本存在异常处理不当漏洞，该漏洞源于在运行挂载后钩子前未检查挂载辅助程序退出状态，导致低权限用户可在挂载辅助程序失败后利用X-mount.idmap或X-mount.owner钩子，克隆具有继承suid位的文件系统或修改目标inode权限，从而实现权限提升。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
util-linux util-linux 2.39 ~ 2.41.6 -

II. Public POCs for CVE-2026-76642

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III. Intelligence Information for CVE-2026-76642

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Patches & Fixes for CVE-2026-76642 (3)

Vendor Advisories for CVE-2026-76642 (1)

Vendor Pages for CVE-2026-76642 (1)

IV. Related Vulnerabilities

Same product: util-linux
Same vendor: util-linux
Same weakness: CWE-390

V. Comments for CVE-2026-76642

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