Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:HSummary
CVE-2026-34448 is a critical-severity Cross-site Scripting (CWE-79) vulnerability in B3Log Siyuan. Its CVSS base score is 9.0 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 40th 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-2026-34448 is a stored cross-site scripting (XSS) vulnerability, associated with CWE-79 (Improper Neutralization of Input During Web Page Generation) and CWE-94 (Improper Control of Generation of Code), affecting SiYuan, a personal knowledge management system, in versions prior to 3.6.2. The flaw occurs in the Attribute View Asset field, where the vulnerable code accepts arbitrary HTTP(S) URLs without file extensions as images. These URLs are stored in a coverURL variable and injected directly into an <img src="..."> attribute without escaping, enabling stored XSS when a victim opens the Gallery or Kanban view with the "Cover From -> Asset Field" option enabled.
An attacker with low privileges (PR:L) can exploit this by placing a malicious URL in an Asset field. When a victim user interacts (UI:R) by opening the affected view, the payload triggers in the Electron desktop client, where nodeIntegration is enabled and contextIsolation is disabled. This allows the injected JavaScript to execute with full access, escalating to arbitrary operating system command execution under the victim's account privileges. The vulnerability's CVSS v3.1 base score of 9.0 (AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H) reflects its high severity due to network accessibility, low complexity, and scope change leading to complete confidentiality, integrity, and availability impacts.
Mitigation is available via the patch in SiYuan version 3.6.2, as detailed in the project's release notes and security advisory. Security practitioners should advise users to update immediately and review configurations disabling "Cover From -> Asset Field" in Gallery or Kanban views as an interim measure. Additional details are provided in the GitHub security advisory (GHSA-rx4h-526q-4458), issue tracker (#17246), and release page (v3.6.2).
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17675
Vulnerability Data
SiYuan is a personal knowledge management system. Prior to version 3.6.2, an attacker who can place a malicious URL in an Attribute View mAsse field can trigger stored XSS when a victim opens the Gallery or Kanban view with “Cover…
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From -> Asset Field” enabled. The vulnerable code accepts arbitrary http(s) URLs without extensions as images, stores the attacker-controlled string in coverURL, and injects it directly into an <img src="..."> attribute without escaping. In the Electron desktop client, the injected JavaScript executes with nodeIntegration enabled and contextIsolation disabled, so the XSS reaches arbitrary OS command execution under the victim’s account. This issue has been patched in version 3.6.2.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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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.
Least privilege limits the damage an injected code fragment can perform once executed.
Requiring documented secure development standards and tools enforces use of safe code-generation APIs and escaping.
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).
PR.DS-10 protects runtime data confidentiality/integrity but has no bearing on neutralizing externally influenced input during code generation, so neither direction shows any preventive effect.
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.