# CVE-2026-82651: SiYuan before v3.8.1 Missing Authorization via /history and /repo/diff

> An authenticated administrator can bypass path restrictions to read sensitive historical files, including plaintext passwords, in SiYuan.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Aug 2026
- **Updated:** 31 Aug 2026
- **Also known as:** GHSA-3cm4-ccvw-6xr6, GHSA-j8f5-rf5j-w7pm, GO-2026-6662

## What is CVE-2026-82651?

CVE-2026-82651 is a medium-severity missing authorization vulnerability in siyuan-note siyuan, published on 30 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

SiYuan before v3.8.1 does not apply the IsForbiddenAbsPath guard (introduced in GHSA-c8r8-95hg-mp34) to the /history/*path and /repo/diff/*path endpoints in kernel/server/serve.go. These routes require admin authentication but construct file paths independently, so an authenticated administrator can retrieve historical snapshots of sensitive files that the guard is meant to block, including data/.siyuan/publishAccess.json (plaintext publish-mode passwords) and files under data/templates/.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-82651?

3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260816034002-035bf9a8c311 |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260816034002-035bf9a8c311 |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260816034002-035bf9a8c311 |

## How do I fix CVE-2026-82651?

Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260816034002-035bf9a8c311 or later.

## Is CVE-2026-82651 being exploited?

There is no known exploitation of CVE-2026-82651 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82651 and fix it if it is affected.

What it is: CVE-2026-82651 is a medium-severity missing authorization vulnerability in siyuan-note siyuan, published on 30 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-82651 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 0.0.0-20260816034002-035bf9a8c311
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260816034002-035bf9a8c311
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260816034002-035bf9a8c311

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-2026-82651/ (Markdown: https://insights.sbomify.com/CVE-2026-82651/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82651
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82651
- OSV: https://osv.dev/vulnerability/CVE-2026-82651

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82651/
Summaries are generated and may contain mistakes; the official description above is the record.