Cyber Resilience

CVE-2026-33476

Path Traversal in B3Log Siyuan ≤ 3.6.2

Public PoCPath Traversal
Published
20 March 2026
Modified
23 March 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.033 87th percentile
Risk Priority 64 floored blend · peak EPSS

Summary

CVE-2026-33476 is a high-severity Path Traversal (CWE-22) vulnerability in B3Log Siyuan. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked in the top 13% of CVEs by exploit likelihood; 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 AC-3 (Access Enforcement) 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-2026-33476 is a directory traversal vulnerability (CWE-22, CWE-73) affecting SiYuan, a personal knowledge management system. Prior to version 3.6.2, the SiYuan kernel exposes an unauthenticated file-serving endpoint under `/appearance/*filepath`. Due to improper path sanitization, this endpoint allows attackers to perform directory traversal and read arbitrary files accessible to the server process. Authentication checks explicitly exclude this endpoint, enabling exploitation without valid credentials.

The vulnerability has a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N), indicating it can be exploited remotely over the network by unauthenticated attackers with low complexity and no user interaction. Successful exploitation grants access to sensitive files readable by the server process, resulting in high confidentiality impact but no integrity or availability disruption.

SiYuan version 3.6.2 addresses this issue. Mitigation details are available in the GitHub security advisory GHSA-hhgj-gg9h-rjp7 and the fixing commit 009bb598b3beccc972aa5f1ed88b3b224326bf2a.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access ControlA06:2025 Insecure Design

EU & UK References

Vulnerability Data

SiYuan is a personal knowledge management system. Prior to version 3.6.2, the Siyuan kernel exposes an unauthenticated file-serving endpoint under `/appearance/*filepath.` Due to improper path sanitization, attackers can perform directory traversal and read arbitrary files accessible to the server process.…

more

Authentication checks explicitly exclude this endpoint, allowing exploitation without valid credentials. Version 3.6.2 fixes this issue.

CWE(s)
CWE-22CWE-73

Related Threats

MITRE ATT&CK Enterprise Techniques

T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
T1083 File and Directory Discovery Discovery
Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1574.007 Path Interception by PATH Environment Variable Stealth
Adversaries may execute their own malicious payloads by hijacking environment variables used to load libraries.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-32749Same product: B3Log Siyuan
CVE-2026-23851Same product: B3Log Siyuan
CVE-2026-33194Same product: B3Log Siyuan
CVE-2026-25992Same product: B3Log Siyuan
CVE-2025-67488Same product: B3Log Siyuan
CVE-2024-55657Same product: B3Log Siyuan
CVE-2024-55658Same product: B3Log Siyuan
CVE-2026-23850Same product: B3Log Siyuan
CVE-2026-25539Same product: B3Log Siyuan
CVE-2026-33670Same product: B3Log Siyuan

Affected Assets

b3log
siyuan
≤ 3.6.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.3.2

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement good match

Enforces the intended directory access authorizations that path traversal would otherwise bypass.

SI-10 Information Input Validation good match

Input validation directly neutralizes special path elements before pathname construction occurs.

AC-6 Least Privilege partial match

Least privilege reduces the impact of any unauthorized file access obtained via traversal.

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.

PR.PS-06 full match
prevents

Secure SDLC practices include input validation and path sanitization that eliminate this weakness.

PR.AA-05 mostly match
prevents

Least-privilege file authorization directly limits damage from externally controlled paths.

PR.PS-02 partial match
prevents

Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.

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.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development catches path traversal via static/dynamic analysis.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.

A.8.26 Application security requirements partial match
prevents

Application security requirements include rules for safe file handling and canonicalization.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles require least-privilege file access and directory isolation.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.

A.8.3 Information access restriction partial match
mitigates

Information access restriction limits which files an application may read or write.

References