CVE-2026-27177
XSS in Mjdm Majordomo
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-27177 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Mjdm Majordomo. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 10th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-27177 is a stored cross-site scripting (XSS) vulnerability in MajorDoMo (also known as Major Domestic Module), an open-source home automation and IoT management platform. The issue affects the unauthenticated /objects/?op=set endpoint, which is designed for IoT device integration and accepts user-supplied property values without sanitization, storing them raw in the database. When an administrator accesses the property editor in the admin panel, these values are rendered without escaping in a paragraph tag (SOURCE field) and a textarea element (VALUE field), triggering the XSS payload automatically on page load without user interaction. The vulnerability is rated 7.2 on the CVSS v3.1 scale (AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N) and maps to CWE-79.
Any unauthenticated attacker with network access can exploit this vulnerability by enumerating properties through the unauthenticated /api.php/data/ endpoint and injecting malicious JavaScript into any property via the /objects/?op=set endpoint. Upon an administrator viewing the affected property editor, the XSS executes in the admin's browser context, enabling theft of sensitive data. The session cookie lacks the HttpOnly flag, allowing attackers to exfiltrate it via document.cookie for full session hijacking, potentially granting unauthorized admin access to the MajorDoMo instance.
Advisories from VulnCheck and Chocapikk detail the vulnerability and proof-of-concept exploitation, while a patch addressing the sanitization and HttpOnly issues is available in GitHub pull request #1177 for the sergejey/majordomo repository.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-8389
Vulnerability Data
MajorDoMo (aka Major Domestic Module) contains a stored cross-site scripting (XSS) vulnerability via the /objects/?op=set endpoint, which is intentionally unauthenticated for IoT device integration. User-supplied property values are stored raw in the database without sanitization. When an administrator views the…
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property editor in the admin panel, the stored values are rendered without escaping in both a paragraph tag (SOURCE field) and a textarea element (VALUE field). The XSS fires on page load without requiring any click from the admin. Additionally, the session cookie lacks the HttpOnly flag, enabling session hijack via document.cookie exfiltration. An attacker can enumerate properties via the unauthenticated /api.php/data/ endpoint and poison any property with malicious JavaScript.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.1.2V1.3.2
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover missing or incorrect input neutralization through targeted web-application tests.
Input validation directly enforces neutralization of untrusted data before it reaches web output generation.
Output filtering can catch or sanitize unneutralized script content before it is served to users.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).
Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Secure-coding testing and automated code-analysis tools are applied to detect improper neutralization of script-related content during web-page generation.
Knowledge exchange on emerging attack techniques and patches reduces the likelihood that cross-site scripting flaws remain unaddressed in deployed applications.
Operational indicators of compromise for web-application attacks can be incorporated into WAF or input-filtering rules, lowering the likelihood that unsanitized data reaches the browser.
Requiring language-specific secure-coding standards and automated scanning during the SDLC catches missing output encoding or improper neutralization of untrusted data before the software reaches production.
Secure-coding standards, SAST scans and removal of insecure code samples together eliminate the failure to neutralize script content that produces cross-site scripting flaws.
Webpage malware scanning and block-listing of known malicious sites reduce the likelihood that reflected or stored script payloads reach a user’s browser.