Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:NSummary
CVE-2026-32308 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Hackerbay Oneuptime. Its CVSS base score is 7.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 13th 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-2026-32308 is a cross-site scripting (XSS) vulnerability (CWE-79) in OneUptime, an open-source solution for monitoring and managing online services. In versions prior to 10.0.23, the Markdown viewer component processes Mermaid diagrams using a securityLevel set to "loose," which permits interactive event bindings. The resulting SVG output is injected into the page via innerHTML, allowing attackers to leverage Mermaid's click directive to execute arbitrary JavaScript. This affects any user-input fields that render Markdown content, such as incident descriptions, status page announcements, and monitor notes. The vulnerability has a CVSS v3.1 base score of 7.6 (AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N).
An authenticated attacker with low privileges (PR:L) can exploit this vulnerability over the network (AV:N) by injecting a malicious Mermaid diagram into a vulnerable Markdown field. The attack requires low complexity (AC:L) and user interaction (UI:R), such as a victim clicking on the rendered diagram, which triggers the click directive to execute JavaScript in the context of the application (S:C). Successful exploitation enables high-impact confidentiality violations (C:H), such as stealing session cookies, tokens, or sensitive data viewed by the victim, with low integrity impact (I:L) and no availability disruption (A:N).
The OneUptime security advisory at https://github.com/OneUptime/oneuptime/security/advisories/GHSA-wvh5-6vjm-23qh details the issue and confirms the fix in version 10.0.23, which addresses the insecure Mermaid rendering configuration. Security practitioners should upgrade to 10.0.23 or later and review any custom Markdown rendering implementations for similar misconfigurations involving SVG injection or loose security policies in diagramming libraries.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-11720
Vulnerability Data
OneUptime is a solution for monitoring and managing online services. Prior to 10.0.23, the Markdown viewer component renders Mermaid diagrams with securityLevel: "loose" and injects the SVG output via innerHTML. This configuration explicitly allows interactive event bindings in Mermaid diagrams,…
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enabling XSS through Mermaid's click directive which can execute arbitrary JavaScript. Any field that renders markdown (incident descriptions, status page announcements, monitor notes) is vulnerable. This vulnerability is fixed in 10.0.23.
- 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.