Medium · CVSS 6.5CVE-2026-59157GHSA-V25G-MVWR-F5FP

webhookd: Unrestricted HTTP Header to Shell Variable InjectionCVE-2026-59157

Answer in brief

CVE-2026-59157 records a Medium severity (CVSS 6.5) vulnerability in webhookd: Unrestricted HTTP Header to Shell Variable Injection. The current sources do not mark it as known exploited. The current feed maps ncarlier/webhookd (generic), github.com/ncarlier/webhookd (go), github.com/ncarlier/webhookd (go). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 15, 2026Updated Sep 30, 2026Source checked Oct 25, 2026First seen by HOL Sep 9, 2026Material review Sep 30, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.5
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps ncarlier/webhookd (generic), github.com/ncarlier/webhookd (go), github.com/ncarlier/webhookd (go). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
ncarlier/webhookdgeneric	<1.22	1.22
github.com/ncarlier/webhookdgo	<1.22.0	1.22.0
github.com/ncarlier/webhookdgo	>=0 <1.22.0	1.22.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for ncarlier/webhookd, github.com/ncarlier/webhookd, github.com/ncarlier/webhookd.
Review the reported fix. Update ncarlier/webhookd to 1.22; github.com/ncarlier/webhookd to 1.22.0; github.com/ncarlier/webhookd to 1.22.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 15, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 9, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.