CVE-2026-42273
HighSummary
Heimdall, an identity-aware proxy and access control service, prior to version 0.17.14, performed host matching in a case-sensitive manner, which is inconsistent with the fact that HTTP hostnames are case-insensitive. This can lead to misclassification of requests that differ only in letter casing.
Risk Assessment
Organizations may face security issues when requests are misclassified, potentially leading to unauthorized access or improper application of access rules.
Recommendation
It is recommended to upgrade to version 0.17.14 or later to eliminate the case sensitivity issue in host matching.
Other vulnerabilities in Heimdall
See all- CVE-2026-42274High
Heimdall prior to version 0.17.14 performs rule matching on the raw request path, which may lead to unauthorized access. Due to the discrepancy in path normalization, Heimdall may authorize requests for one path while downstream components process a different, normalized path.
- CVE-2026-42272High
Heimdall, a proxy and access control service, prior to version 0.17.14 handled URL-encoded slashes in a case-sensitive manner, leading to request path interpretation issues. As a result, the lowercase equivalent (%2f) was not recognized, potentially resulting in authorization bypass.
- CVE-2026-107449Low
linuxserver Heimdall through 2.8.3 applies its SafeUrlFetcher SSRF protection only to ItemController; the enhanced-application test and live-stats requests occur via SupportedApps::execute(), a GuzzleHttp client that lacks IP address restrictions. In some realistic installations, the POST /test_config (and GET /get_stats) endpoints are accessible through CSRF, allowing an unauthenticated attacker to force the server to send requests to arbitrary internal hosts and ports (including 169.254.169.254) and read a status/port oracle in addition to partial response data.
- CVE-2026-82477Medium
In MITRE SAF Heimdall 2.11.6 through 2.13.x before 2.14.0, an SSRF issue allows remote attackers to access internal network resources via the Tenable proxy endpoint. This occurs in apps/backend/src/tenable/tenable.controller.ts.
Original NVD description (English source)
Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.14, Heimdall performs host matching in a case-sensitive manner, while HTTP hostnames are case-insensitive. This discrepancy can result in heimdall failing to match a rule for a request host that differs only in letter casing, potentially causing the request to be classified differently than intended. This issue has been patched in version 0.17.14.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS