CVE-2026-32947— Egress Policy Bypass via DNS over HTTPS (DoH) in Harden-Runner (Community Tier)
Quick assessment
Affected
step-security harden-runner
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.
Harden-Runner是StepSecurity开源的一个程序。为 GitHub 托管和自托管的跑步者提供网络出口过滤和运行时安全。 Harden-Runner 2.15.1及之前版本存在安全漏洞，该漏洞源于DNS over HTTPS漏洞允许通过允许的HTTPS端点隧道传输数据，从而绕过出口策略网络限制。
Possible ATT&CK Techniques 2 AI
T1048.003 · Exfiltration Over Unencrypted Non-C2 Protocol T1071.004 · DNS
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I. Basic Information for CVE-2026-32947
Vulnerability Information
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Vulnerability Title
Egress Policy Bypass via DNS over HTTPS (DoH) in Harden-Runner (Community Tier)
Source: CVE Program / CVE List V5
Vulnerability Description
Harden-Runner is a CI/CD security agent that works like an EDR for GitHub Actions runners. In versions 2.15.1 and below, a DNS over HTTPS (DoH) vulnerability allows attackers to bypass egress-policy: block network restrictions by tunneling exfiltrated data through permitted HTTPS endpoints like dns.google. The attack works by encoding sensitive data (e.g., the runner's hostname) as subdomains in DoH queries, which appear as legitimate HTTPS traffic to Harden-Runner's domain-based filtering but are ultimately forwarded to an attacker-controlled domain. This effectively enables data exfiltration without directly connecting to any blocked destination. Exploitation requires the attacker to already have code execution within the GitHub Actions workflow. The issue was fixed in version 2.16.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
保护机制失效
Source: CVE Program / CVE List V5
Vulnerability Title
Harden-Runner 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Harden-Runner是StepSecurity开源的一个程序。为 GitHub 托管和自托管的跑步者提供网络出口过滤和运行时安全。 Harden-Runner 2.15.1及之前版本存在安全漏洞，该漏洞源于DNS over HTTPS漏洞允许通过允许的HTTPS端点隧道传输数据，从而绕过出口策略网络限制。
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 |
|---|---|---|---|---|
| step-security | harden-runner | < 2.16 | - |
|
II. Public POCs for CVE-2026-32947
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-32947 (1)
-
Release v2.16.0 · step-security/harden-runner · GitHub x_refsource_MISC
Vendor Advisories for CVE-2026-32947 (1)
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V. Comments for CVE-2026-32947
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