CVE-2026-42274

Heimdall: Authorization bypass via path normalization mismatch

HIGH
7.8
CVSS Score
Published: May 8, 2026 at 03:43 AM UTC
Updated: October 26, 2026 at 08:10 PM UTC
1 product affected across 1 vendorHeimdall

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Severity
HIGH7.8
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.14, 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. This discrepancy can result in heimdall authorizing a request for one path (e.g., /user/../admin, or URL-encoded variants such as /user/%2e%2e/admin or /user/%2e%2e%2fadmin. The latter would require the allow_encoded_slashes option to be set to on or no_decode.) while the downstream ultimately processes a different, normalized path (/admin). This issue has been patched in version 0.17.14.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.17.14
Affected range stops below 0.17.14, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.8HIGHGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-35CWE-436

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