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CVE-2026-100395— LXC: lxc-copy host-context hostname update follows symlink

Quick assessment

Affected
lxc lxc
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.

LXC 是一个用户空间接口，用于利用 Linux 内核的隔离功能来创建和管理系统容器。在 LXC 7.0.0 及更早版本中， 工具和 liblxc 的公开 API 在更新被复制容器根文件系统中的 文件时，可能会跟随由攻击者控制的符号链接。受影响的组件包括 和 liblxc 公开的 API。执行克隆操作的特权进程必须以 root 用户身份运行，且源根文件系统必须由攻击者控制或属于低信任度环境。攻击者可以在 路径或其中间组件中放置符号链接。克隆操作会在更新主机名之前保留该符号链接。存在漏洞的写操作会截断并覆盖位于目标根

CVSS 6.8 · Medium

Possible ATT&CK Techniques 1 AI

T1565.003 · Runtime Data Manipulation
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I. Basic Information for CVE-2026-100395

Vulnerability Information
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Vulnerability Title
LXC: lxc-copy host-context hostname update follows symlink
Source: CVE Program / CVE List V5
Vulnerability Description
LXC is a userspace interface for the Linux kernel containment features used to create and manage system containers. In LXC 7.0.0 and earlier, lxc-copy and the public liblxc clone() API can follow attacker-controlled symbolic links while updating /etc/hostname in a copied container root filesystem. The affected surfaces are lxc-copy and liblxc's public lxc_container::clone() API. The privileged cloning process must run as root. The source rootfs must be attacker-controlled or less trusted. A symlink can be placed at etc/hostname or in an intermediate component. The clone operation preserves the symlink before updating the hostname. The vulnerable write truncates and overwrites an existing file outside the destination rootfs. When root clones an untrusted container without LXC_CLONE_KEEPNAME, the copied symlink can resolve outside the destination rootfs and cause the privileged process to overwrite an existing host file with the destination container name. Unprivileged use and managers with independent cloning implementations are not affected. LXC_CLONE_KEEPNAME avoids the hostname update and therefore the affected write.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
在文件访问前对链接解析不恰当(链接跟随)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
lxc lxc <= 7.0.0 -

II. Public POCs for CVE-2026-100395

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III. Intelligence Information for CVE-2026-100395

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Other References for CVE-2026-100395 (3)

IV. Related Vulnerabilities

Same product: lxc
Same vendor: lxc
Same weakness: CWE-59