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.
CVE-2026-59157
MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence
This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 61% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, secondary
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.5
- EG Score
- 6.5(medium)
- EG Risk
- 44(Track)EG Risk 44/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity65% × 45%Exploitation0% × 40%Automatability100% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 39%
- KEV
- Not listed
Published
September 9, 2026
Last Modified
September 16, 2026
Advisory Details (4)
Auto-updated Sep 15, 2026Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available
v1.22.0
Patch available: ncarlier/webhookd v1.22.0
https://github.com/ncarlier/webhookd/releases/tag/v1.22.0github_commit Patch Available
commit 5ac66677bf72 (ncarlier/webhookd)
Patch available: ncarlier/webhookd v1.22.0 (contains commit 5ac66677bf72)
https://github.com/ncarlier/webhookd/commit/5ac66677bf7224191f1dfc51a875b09187d10bebgithub_pr Patch Available
feat: optional filtering on upstream HTTP headers
Patch available: ncarlier/webhookd v1.22.0 (PR #121 merged 2026-06-20)
https://github.com/ncarlier/webhookd/pull/121github Patch Available
Unrestricted HTTP Header to Shell Variable Injection · Advisory · ncarlier/webhookd · GitHub
https://github.com/ncarlier/webhookd/security/advisories/GHSA-v25g-mvwr-f5fpVendor Advisories for CVE-2026-59157(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
Go(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| github.com/ncarlier/webhookd | — | 1.22.0 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 9× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-09-18 21:45 UTCEG score recompute
- 2026-09-18 19:28 UTCEPSS rescore
- 2026-09-17 20:14 UTCEG score recompute
- 2026-09-17 19:31 UTCEPSS rescore
- 2026-09-16 16:56 UTCEG score recompute
- 2026-09-16 15:45 UTCEG score recompute
- 2026-09-16 14:08 UTCEPSS rescore
- 2026-09-15 16:35 UTCEG score recompute
- 2026-09-10 00:25 UTCEG score recompute
Frequently asked(5)
What is CVE-2026-59157?
CVE-2026-59157 is a medium vulnerability published on September 9, 2026. 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…
When was CVE-2026-59157 disclosed?
CVE-2026-59157 was first published in the National Vulnerability Database on September 9, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59157 actively exploited?
CVE-2026-59157 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 60.8% of all scored CVEs.
What is the CVSS score of CVE-2026-59157?
CVE-2026-59157 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-59157?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59157, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-59157
Is Your Infrastructure Affected by CVE-2026-59157?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.