CVE-2026-59157: CWE-290: Authentication Bypass by Spoofing in ncarlier webhookd
webhookd is a minimalist webhook server that triggers shell scripts and external processes through HTTP requests. Prior to 1.22.0, webhookd deployments without htpasswd authentication forwarded all incoming HTTP headers through HTTPParamsToShellVars in pkg/api/index.go into the hook script environment without an allowlist. When an upstream reverse proxy did not strip a client-supplied X-WebAuthn-User header and a hook script trusted that variable for identity or privilege, a remote unauthenticated attacker could spoof another user, bypass script security controls, and access or modify resources available to the impersonated identity. This issue is fixed in version 1.22.0.
AI Analysis
Technical Summary
webhookd is a minimalist webhook server that triggers shell scripts via HTTP requests. Before version 1.22.0, deployments without htpasswd authentication forwarded all HTTP headers into the hook script environment without filtering. An attacker can exploit this by sending a spoofed X-WebAuthn-User header if the upstream proxy does not strip it, enabling authentication bypass by impersonating another user. This allows unauthorized access or modification of resources accessible to the impersonated identity. The vulnerability is addressed in version 1.22.0.
Potential Impact
A remote unauthenticated attacker can spoof the X-WebAuthn-User header to bypass authentication controls in webhookd hook scripts, potentially gaining unauthorized access or modifying resources associated with the impersonated user. The impact includes limited confidentiality and integrity loss but no availability impact.
Mitigation Recommendations
Upgrade webhookd to version 1.22.0 or later, where this vulnerability is fixed. Ensure that htpasswd authentication is enabled if applicable. Additionally, configure upstream reverse proxies to strip or validate the X-WebAuthn-User header to prevent spoofing. Patch status is confirmed fixed in version 1.22.0.
CVE-2026-59157: CWE-290: Authentication Bypass by Spoofing in ncarlier webhookd
Description
webhookd is a minimalist webhook server that triggers shell scripts and external processes through HTTP requests. Prior to 1.22.0, webhookd deployments without htpasswd authentication forwarded all incoming HTTP headers through HTTPParamsToShellVars in pkg/api/index.go into the hook script environment without an allowlist. When an upstream reverse proxy did not strip a client-supplied X-WebAuthn-User header and a hook script trusted that variable for identity or privilege, a remote unauthenticated attacker could spoof another user, bypass script security controls, and access or modify resources available to the impersonated identity. This issue is fixed in version 1.22.0.
CVSS v3.1
Score 6.5medium
Affected software
ncarlier
webhookd
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
webhookd is a minimalist webhook server that triggers shell scripts via HTTP requests. Before version 1.22.0, deployments without htpasswd authentication forwarded all HTTP headers into the hook script environment without filtering. An attacker can exploit this by sending a spoofed X-WebAuthn-User header if the upstream proxy does not strip it, enabling authentication bypass by impersonating another user. This allows unauthorized access or modification of resources accessible to the impersonated identity. The vulnerability is addressed in version 1.22.0.
Potential Impact
A remote unauthenticated attacker can spoof the X-WebAuthn-User header to bypass authentication controls in webhookd hook scripts, potentially gaining unauthorized access or modifying resources associated with the impersonated user. The impact includes limited confidentiality and integrity loss but no availability impact.
Mitigation Recommendations
Upgrade webhookd to version 1.22.0 or later, where this vulnerability is fixed. Ensure that htpasswd authentication is enabled if applicable. Additionally, configure upstream reverse proxies to strip or validate the X-WebAuthn-User header to prevent spoofing. Patch status is confirmed fixed in version 1.22.0.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-02T16:50:27.887Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aa9688d55bf5e2cf5074e58
Added to database: 09/15/2026, 15:47:25 UTC
Last enriched: 09/15/2026, 16:02:13 UTC
Last updated: 09/16/2026, 02:18:12 UTC
Views: 17
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