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CVE-2026-66897— Instance template path traversal allows arbitrary host file write as root

Quick assessment

Affected
Canonical LXD
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Canonical LXD是英国Canonical公司开源的一款基于Linux系统用于管理应用程序的容器。 Canonical lxd 存在路径遍历漏洞，该漏洞源于实例模板处理过程中，对metadata.yaml中指定的目标模板路径，LXD使用受限的os.Root目录句柄验证路径，但随后使用未受限的字符串路径通过os.Create打开并创建文件，导致路径解析检查与文件创建不一致，攻击者可逃逸目录限制，以root权限覆盖主机上的任意文件，并可能实现主机root代码执行。

CVSS 9.9 · Critical EPSS 0.72% · P53

Affected Version Matrix 4

VendorProduct Version RangeStatus
Canonical LXD 4.0.0< 4.0.13 affected
5.0.0< 5.0.9 affected
5.21.0< 5.21.7 affected
6.0< 6.10 affected
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I. Basic Information for CVE-2026-66897

Vulnerability Information
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Vulnerability Title
Instance template path traversal allows arbitrary host file write as root
Source: CVE Program / CVE List V5
Vulnerability Description
A path traversal vulnerability in LXD's instance template processing allows an attacker with container edit permissions, or any user launching a crafted image, to overwrite arbitrary files on the host system as root. When processing target template paths specified in metadata.yaml, LXD validates the path against a confined os.Root directory handle but subsequently opens and creates the file using os.Create with an unconfined string path. This discrepancy between path resolution checks and file creation allows an attacker to escape directory confinement, overwrite root-owned host files, and achieve host root code execution.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
对路径名的限制不恰当(路径遍历)
Source: CVE Program / CVE List V5
Vulnerability Title
Canonical lxd 路径遍历漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Canonical LXD是英国Canonical公司开源的一款基于Linux系统用于管理应用程序的容器。 Canonical lxd 存在路径遍历漏洞，该漏洞源于实例模板处理过程中，对metadata.yaml中指定的目标模板路径，LXD使用受限的os.Root目录句柄验证路径，但随后使用未受限的字符串路径通过os.Create打开并创建文件，导致路径解析检查与文件创建不一致，攻击者可逃逸目录限制，以root权限覆盖主机上的任意文件，并可能实现主机root代码执行。
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
Canonical LXD 4.0.0 ~ 4.0.13 -

II. Public POCs for CVE-2026-66897

# POC Description Source Link Shenlong Link
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Qwen3.6-35B-A3B · 14236 chars
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III. Intelligence Information for CVE-2026-66897

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Vendor Advisories for CVE-2026-66897 (1)

IV. Related Vulnerabilities

Same product: LXD
Same vendor: Canonical
Same weakness: CWE-22

V. Comments for CVE-2026-66897

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