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CVE-2026-40318

B3log Siyuan path traversal

8.5 HIGHEPSS 0.44%
  1. Published16 Apr 2026

Description

SiYuan is an open-source personal knowledge management system. In versions 3.6.3 and prior, the /api/av/removeUnusedAttributeView endpoint constructs a filesystem path using the user-controlled id parameter without validation or path boundary enforcement. An attacker can inject path traversal sequences such as ../ into the id value to escape the intended directory and delete arbitrary .json files on the server, including global configuration files and workspace metadata. This issue has been fixed in version 3.6.4.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeChanged
ConfidentialityNone
IntegrityLow
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H

Affected products

B3log Siyuan< 3.6.4

Remediation

Fixed in
B3log Siyuan≥ 3.6.4

References

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Frequently asked

Is CVE-2026-40318 being actively exploited?

CVE-2026-40318 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.44%.

How severe is CVE-2026-40318?

CVE-2026-40318 has a CVSS 3.1 base score of 8.5, rated high. EPSS estimates a 0.44% probability of exploitation.

Which products are affected by CVE-2026-40318?

Affected products include B3log Siyuan.

How do I fix CVE-2026-40318?

Upgrade affected software to a fixed version, for example B3log Siyuan 3.6.4 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-40318 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.