VulnerabilityPublished 20 Mar 2026Updated 21 Mar 2026

CVE-2026-32811: dadrus heimdall · Improper Encoding or Escaping of Output

Affects dadrus heimdallSource CVE Database V5

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Not known to be exploited · CVSS 8.2 High : upgrade to 0.17.11 soon.

Data as of 31 Oct 2026, 20:20 UTC

CVSS 3.1 base score

8.2High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 24% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.17.11

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade dadrus heimdall to 0.17.11.

Affected software

Product	Affected	Fixed in
dadrusheimdall	Affected >=0.7.0-alpha <0.17.11	Fixed in 0.17.11

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AI-suggested

Upgrade Heimdall to version 0.17.11 or later to apply the official fix for this vulnerability.
Avoid using insecure default configurations; do not disable secure default rule enforcement unless absolutely necessary and fully understood.
Review and audit all access control rules to ensure they do not rely solely on path matching that could be bypassed by URL encoding issues.
Implement additional layers of access control and monitoring around Heimdall to detect anomalous access patterns.
Use network segmentation and zero trust principles to limit the impact of any potential bypass.
Regularly update and patch Heimdall and related components to incorporate security improvements.
Conduct penetration testing and vulnerability assessments focusing on URL encoding and access control logic.
Monitor Heimdall logs for unusual requests that include encoded query strings in paths.
Educate DevOps and security teams about the risks of disabling secure defaults and the importance of proper URL handling in access control.

Description

Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. When using Heimdall in envoy gRPC decision API mode with versions 0.7.0-alpha through 0.17.10, wrong encoding of the query URL string allows rules with non-wildcard path expressions to be bypassed. Envoy splits the requested URL into parts, and sends the parts individually to Heimdall. Although query and path are present in the API, the query field is documented to be always empty and the URL query is included in the path field. The implementation uses go's url library to reconstruct the url which automatically encodes special characters in the path. As a consequence, a parameter like /mypath?foo=bar to Path is escaped into /mypath%3Ffoo=bar. Subsequently, a rule matching /mypath no longer matches and is bypassed. The issue can only lead to unintended access if Heimdall is configured with an "allow all" default rule. Since v0.16.0, Heimdall enforces secure defaults and refuses to start with such a configuration unless this enforcement is explicitly disabled, e.g.via --insecure-skip-secure-default-rule-enforcement or the broader --insecure flag. This issue has been fixed in version 0.17.11.

Impact

This vulnerability can allow attackers to bypass path-based access control rules in Heimdall, potentially granting unauthorized access to protected resources. The impact primarily affects confidentiality and integrity of access control decisions, as unauthorized users may gain access to sensitive services or data. Availability is not impacted. The risk is significant in environments where Heimdall is deployed as a critical identity-aware proxy controlling access to cloud-native applications and services. Organizations using vulnerable versions with insecure default configurations are at higher risk. Exploitation requires no authentication or user interaction and can be performed remotely over the network, increasing the threat surface. However, secure default configurations in recent versions mitigate the risk unless explicitly disabled. Failure to patch or properly configure Heimdall could lead to unauthorized data exposure, privilege escalation, and potential lateral movement within enterprise networks.

CWE-116Improper Encoding or Escaping of Output (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Parameterization
If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated.
Architecture and Design · Implementation
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
OWASP Cheat Sheets
Content Security Policy (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
Query Parameterization (opens in a new tab)
OWASP ASVS 4.0.3
V14.4.6 (opens in a new tab)
V14.4.4 (opens in a new tab)
V14.4.2 (opens in a new tab)
Attack patterns
Cross Zone Scripting (opens in a new tab)
User-Controlled Filename (opens in a new tab)
Web Server Logs Tampering (opens in a new tab)
AJAX Footprinting (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-863Incorrect Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #17OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Mar 2026, 19:30 UTC

WeaknessesCWE-116, CWE-863

Technical details

References

Community reviews

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