# CVE-2026-23851: SiYuan Vulnerable to Arbitrary File Read via File Copy Functionality > Authenticated attackers can read arbitrary files from the server filesystem via the globalCopyFiles API due to missing path validation. - **Severity:** High 8.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 19 Jan 2026 - **Updated:** 20 Jan 2026 - **Also known as:** GHSA-94c7-g2fj-7682, GO-2026-4346 ## What is CVE-2026-23851? CVE-2026-23851 is a high-severity path traversal vulnerability in B3log Siyuan, published on 19 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim. ### Official 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. Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) ## Which versions are affected by CVE-2026-23851? 3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260118092521-f8f4b517077b | | `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260118092521-f8f4b517077b | | `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260118092521-f8f4b517077b | Products: B3log Siyuan. ## How do I fix CVE-2026-23851? Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260118092521-f8f4b517077b or later. ## Is CVE-2026-23851 being exploited? There is no known exploitation of CVE-2026-23851 in the wild and no public exploit code. ## Other vulnerabilities in B3log Siyuan - [CVE-2026-32938](https://insights.sbomify.com/CVE-2026-32938/): SiYuan has an Arbitrary File Read in its Desktop Publish Service (critical 9.9) - [CVE-2026-33669](https://insights.sbomify.com/CVE-2026-33669/): SiYuan has Arbitrary Document Reading within the Publishing Service (critical 9.8) - [CVE-2026-33670](https://insights.sbomify.com/CVE-2026-33670/): SiYuan has directory traversal within its publishing service (critical 9.8) - [CVE-2026-32767](https://insights.sbomify.com/CVE-2026-32767/): SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API (critical 9.8) - [CVE-2024-53504](https://insights.sbomify.com/CVE-2024-53504/): SQL injection in n/a (critical 9.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-23851 and fix it if it is affected. What it is: CVE-2026-23851 is a high-severity path traversal vulnerability in B3log Siyuan, published on 19 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-23851 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260118092521-f8f4b517077b - github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260118092521-f8f4b517077b - github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260118092521-f8f4b517077b Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-23851/ (Markdown: https://insights.sbomify.com/CVE-2026-23851/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23851 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23851 - OSV: https://osv.dev/vulnerability/CVE-2026-23851 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-23851/ Summaries are generated and may contain mistakes; the official description above is the record.