How severe is CVE-2026-23851?

CVE-2026-23851 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-23851 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-23851?

CVE-2026-23851 affects B3log Siyuan. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-23851?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-23851 have an EU (EUVD) identifier?

Yes. CVE-2026-23851 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3291.

When was CVE-2026-23851 published?

CVE-2026-23851 was published on 2026-01-19 and last updated on 2026-06-17.

CVE-2026-23851

CVE-2026-23851 is a medium-severity vulnerability in B3log Siyuan with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v4: 8.3
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-3291
Weakness: CWE-22
Affected product: B3log Siyuan
Published: 2026-01-19
Last modified: 2026-06-17

Description

SiYuan is a personal knowledge management system. Versions prior to 3.5.4 contain a logic vulnerability in the /api/file/globalCopyFiles endpoint. The function allows authenticated users to copy files from any location on the server's filesystem into the application's workspace without proper path validation. The vulnerability exists in the api/file.go source code. The function globalCopyFiles accepts a list of source paths (srcs) from the JSON request body. While the code checks if the source file exists using filelock.IsExist(src), it fails to validate whether the source path resides within the authorized workspace directory. Version 3.5.4 patches the issue.

Frequently asked questions

What is CVE-2026-23851?: SiYuan is a personal knowledge management system. Versions prior to 3.5.4 contain a logic vulnerability in the /api/file/globalCopyFiles endpoint. The function allows authenticated users to copy files from any location on the server's filesystem into the application's workspace without proper path validation. The vulnerability exists in the api/file.go source code. The function globalCopyFiles accepts a list of source paths (srcs) from the JSON request body. While the code checks if the source file exists using filelock.IsExist(src), it fails to validate whether the source path resides within the authorized workspace directory. Version 3.5.4 patches the issue.
How severe is CVE-2026-23851?: CVE-2026-23851 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-23851 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23851?: CVE-2026-23851 affects B3log Siyuan. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-23851?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-23851 have an EU (EUVD) identifier?: Yes. CVE-2026-23851 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3291.
When was CVE-2026-23851 published?: CVE-2026-23851 was published on 2026-01-19 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*

More vulnerabilities in B3log Siyuan

CVE-2026-32938 — Critical (CVSS 9.9): SiYuan is a personal knowledge management system. In versions 3.6.0 and below, the /api/lute/html2BlockDOM on the…
CVE-2026-33670 — Critical (CVSS 9.8): SiYuan is a personal knowledge management system. Prior to version 3.6.2, the /api/file/readDir interface was used to…
CVE-2026-33669 — Critical (CVSS 9.8): SiYuan is a personal knowledge management system. Prior to version 3.6.2, document IDs were retrieved via the…
CVE-2026-32767 — Critical (CVSS 9.8): SiYuan is a personal knowledge management system. Versions 3.6.0 and below contain an authorization bypass…
CVE-2024-55660 — Critical (CVSS 9.8): SiYuan is a personal knowledge management system. Prior to version 3.1.16, SiYuan's `/api/template/renderSprig`…
CVE-2024-53507 — Critical (CVSS 9.8): A SQL injection vulnerability was discovered in Siyuan 3.1.11 in /getHistoryItems.

All CVEs affecting B3log Siyuan →

Other CWE-22 (Path Traversal) vulnerabilities

CVE-2026-48282 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Limitation of a Pathname to a Restricted…
CVE-2026-54917 — Critical (CVSS 10.0): SeaweedFS is a distributed storage system for object storage (S3), file systems, and Iceberg tables. Prior to 4.30, the…
CVE-2026-11429 — Critical (CVSS 10.0): Two endpoints in the Vault Service ScriptsController, shared by Altium Enterprise Server and Altium 365, accept file…
CVE-2026-34909 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi OS devices to…
CVE-2026-7411 — Critical (CVSS 10.0): In Eclipse BaSyx Java Server SDK versions prior to 2.0.0-milestone-10, inadequate path normalization in the Submodel…
CVE-2026-36767 — Critical (CVSS 10.0): A path traversal vulnerability in the /content/images/add endpoint of shopizer v3.2.5 allows attackers write arbitrary…

Browse all CWE-22 (Path Traversal) vulnerabilities →