# CVE-2026-59157

## Summary

- **CVE ID:** CVE-2026-59157
- **Severity:** MEDIUM
- **CVSS Score:** 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)
- **CWE:** CWE-290, CWE-807
- **Published:** Sep 15, 2026
- **Last Modified:** Sep 16, 2026

## 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.

## Affected Products

- ncarlier — webhookd (< 1.22)

## References

- [CNA](https://github.com/ncarlier/webhookd/security/advisories/GHSA-v25g-mvwr-f5fp)
- [CNA](https://github.com/ncarlier/webhookd/pull/121)
- [CNA](https://github.com/ncarlier/webhookd/commit/5ac66677bf7224191f1dfc51a875b09187d10beb)
- [CNA](https://github.com/ncarlier/webhookd/releases/tag/v1.22.0)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.46%
- **EPSS Percentile:** 39.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._