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CVE-2026-100838— Contrast before 1.19.1 CopyFile Policy Symlink Subversion

Quick assessment

Affected
edgelesssys contrast
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.

Contrast 是 Kubernetes 的一个机密计算运行时环境。在 1.19.1 之前的版本中，由 Contrast CLI 生成的 Kata 代理策略在 CopyFile 验证环节存在缺陷，允许对访客（guest）根文件系统执行任意写入操作。如果不受信任的主机上存在恶意进程，并能连接到 Kata 代理的 VSOCK 接口，就可以发起一系列 CopyFile 请求，从而覆盖访客系统中安全关键的文件，或诱使工作负载泄露敏感数据，实质上等同于完全接管访客系统。 对于暂时无法升级的用户，可以通过运行 命令应用等效的

CVSS 8.1 · High EPSS 0.22% · P11
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I. Basic Information for CVE-2026-100838

Vulnerability Information
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Vulnerability Title
Contrast before 1.19.1 CopyFile Policy Symlink Subversion
Source: CVE Program / CVE List V5
Vulnerability Description
Contrast is a confidential-computing runtime for Kubernetes. In versions before 1.19.1, the Kata agent policies generated by the Contrast CLI contained a flaw in the CopyFile verification that allowed arbitrary writes to the guest root filesystem. A malicious process on the untrusted host able to connect to the Kata agent VSOCK could issue a series of CopyFile requests to overwrite security-critical files in the guest or trick the workload into disclosing sensitive data, effectively amounting to a full guest takeover. Users unable to upgrade can apply an equivalent rego policy fix passed to 'contrast generate --policy'.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A: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
edgelesssys contrast 0 ~ 1.19.1 -

II. Public POCs for CVE-2026-100838

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III. Intelligence Information for CVE-2026-100838

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Vendor Advisories for CVE-2026-100838 (1)

Other References for CVE-2026-100838 (1)

Same Patch Batch · edgelesssys · 2026-09-27 · 11 CVEs total

CVE-2026-100839 8.4 HIGH Contrast before 1.18.0 AML Injection Remote Code Execution
CVE-2026-100833 8.2 HIGH Contrast before 1.23.1 Image Substitution via Policy Generation
CVE-2026-100835 7.4 HIGH Contrast before 1.16.0 Remote Attestation Relay Attack
CVE-2025-71425 7.3 HIGH Contrast before 1.8.1 Information Disclosure via Logging
CVE-2025-71423 7.3 HIGH Edgelesssys Contrast before 1.12.2 Workload Secrets Information Disclosure
CVE-2025-71426 7.1 HIGH Contrast before 1.4.1 Coordinator Impersonation via Unauthenticated Recovery
CVE-2025-71422 5.7 MEDIUM Contrast before 1.12.1 Insecure LUKS2 Persistent Storage
CVE-2026-100836 4.3 MEDIUM Edgeless Systems Contrast through 1.20.0 Denial of Service via ciphertextContainer
CVE-2026-100837 3.7 LOW Edgeless Systems Contrast through 1.20.0 Credential Leak via Registry Suffix Matching
CVE-2025-71424 3.5 LOW Edgeless Systems Contrast before 1.9.1 Insecure Volume Mount

IV. Related Vulnerabilities

Same product: contrast
Same vendor: edgelesssys
Same weakness: CWE-59

V. Comments for CVE-2026-100838

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