Live Exposure Defense: From CVE to Confirmed Exposure in 12 Hours – See more

Back
New CVE Detected

CVE-2026-54167 – GitHub App Credential Exfiltration via Untrusted Enterprise Host Header – Tekton Pi

Be the first to know when new zero-days emerge:

Subscribe to Email Alerts
Subscribe to RSS Feed

Summary

CVE-2026-54167 is an insufficient verification of data authenticity flaw (CWE-345) in Tekton Pipelines-as-Code’s GitHub App provider. Affected versions accept the X-GitHub-Enterprise-Host request header as the target API host when generating a GitHub App installation access token, and do so before the webhook signature is validated or the host is checked against the repository URL in the signed payload. This allows a remote, unauthenticated attacker to redirect the token-generation request to an attacker-controlled host and potentially capture the GitHub App JWT, rated High severity (CVSS 8.2).

Technical details

  • Root cause: When a webhook payload contains an installation.id, Pipelines-as-Code generates a GitHub App JWT and requests an installation access token using the API host supplied in the X-GitHub-Enterprise-Host header, without first validating the webhook signature or confirming that host matches the repository referenced in the signed payload.
  • Trigger conditions: The target Pipelines-as-Code deployment must use the GitHub App provider and expose its webhook endpoint to the attacker (directly or via a proxy that forwards custom headers).
  • Attack vector: Network — an attacker sends a crafted webhook-style HTTP request containing an installation.id and a malicious X-GitHub-Enterprise-Host value pointing to an attacker-controlled server, before signature validation occurs.
  • Impact: The attacker-controlled host can intercept the signed GitHub App JWT sent during token exchange, potentially enabling the attacker to mint unauthorized GitHub App installation access tokens, resulting in high confidentiality impact and limited integrity impact (no direct availability impact).

Affected software

  • tektoncd/pipelines-as-code versions before 0.37.8
  • versions 0.38.0 to before 0.39.6
  • versions 0.40.0 to before 0.42.1
  • versions 0.43.0 to before 0.48.0
    (All versions up to and including 0.47.0 are vulnerable; the fix is first available in the listed patched releases.)

Severity

  • CVSS v3.1 Base Score: 8.2 (High)
  • Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Mitigation and recommended actions

  • Immediate: Upgrade Pipelines-as-Code to v0.37.8, v0.39.6, v0.42.1, v0.48.0, or later, depending on the deployed release line. The fix validates the webhook signature before requesting a token, verifies the Enterprise host against the signed repository URL, and derives the host from the repository URL rather than the request header.
  • If immediate patching is not possible:
    • Strip or block the X-GitHub-Enterprise-Host header at ingress/reverse-proxy layers in front of the Pipelines-as-Code webhook endpoint.
    • For deployments using GitHub.com (not GitHub Enterprise), reject any incoming webhook request that includes this header at all.
    • Restrict network access to the Pipelines-as-Code webhook endpoint to trusted sources (e.g., GitHub’s published webhook IP ranges) where feasible.
    • Rotate the associated GitHub App private key if compromise or exploitation is suspected.

References

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report

How IONIX’s External Exposure Management Platform Detects and Validates
Zero-Days to Shrink MTTR

1

Map your entire attack surface (continously)

IONIX uses multi-factor discovery methods, including DNS analysis, certificate mapping, metadata inspection, and more, to automatically map every internet-facing asset across your environment. This includes cloud instances, third-party platforms, shadow IT, and even forgotten infrastructure that traditional tools miss.

2

Monitor for new CVEs

Dozens of threat intel feeds using agentic technology are continuously analyzed to detect the appearance of proof-of-concept code, exploit kits, and indicators of active targeting. IONIX goes further by applying AI to proactively evaluate whether emerging vulnerabilities are likely to be exploited, even before PoCs go public.

3

Identify Potential External Exposures

Not all CVEs matter. IONIX filters vulnerabilities by asking attacker-centric questions: Can it be reached from the internet? Does it require authentication? Is it being exploited in the wild? This dramatically reduces noise and focuses teams on threats that can actually be weaponized.

4

Create Safe, Scalable Exploit Validations

IONIX transforms real-world PoCs into safe, non-intrusive test payloads that can be run in production environments without disruption. These simulations are precisely targeted to the systems that are vulnerable, ensuring rapid validation without unnecessary load.

5

Execute Exploit Validations

By combining context about software stack, versioning, exposure status, and reachability, IONIX ensures that only the right payloads are executed against the right assets, maximizing efficiency and minimizing risk.

6

Drive Fast and Actionable Remediation

Results are routed through integrations with ticketing, SOAR, and SIEM tools. Issues are written in plain language, bundled into remediation clusters, and prioritized based on asset criticality, exploitability, and blast radius. This shortens mean time to remediation (MTTR) and empowers teams to act with confidence.

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report
Close

Subscribe to Threat Center RSS

Copy/paste the link below into your preferred RSS reader or follow these instructions to subscribe to Slack alerts.

Open RSS feedSlack setup instructions

Close

Get Real-Time CVE Alerts to Your Email

Be the first to know when new zero-days emerge