HedgeDoc (formerly known as CodiMD) is an open-source collab… (CVE-2021-29474)

Summary

Vulnerability reported (CVE-2021-29474). Risk of unauthorized operations or information disclosure. Exploitable via noteController.showNote.

Original description

The description as published by the source.

HedgeDoc (formerly known as CodiMD) is an open-source collaborative markdown editor. An attacker can read arbitrary .md files from the server's filesystem due to an improper input validation, which results in the ability to perform a relative path traversal. To verify if you are affected, you can try to open the following URL: http://localhost:3000/..%2F..%2FREADME# (replace http://localhost:3000 with your instance's base-URL e.g. https://demo.hedgedoc.org/..%2F..%2FREADME#). If you see a README page being rendered, you run an affected version. The attack works due the fact that the internal router passes the url-encoded alias to the noteController.showNote-function. This function passes the input directly to findNote() utility function, that will pass it on the the parseNoteId()-function, that tries to make sense out of the noteId/alias and check if a note already exists and if so, if a corresponding file on disk was updated. If no note exists the note creation-function is called, which pass this unvalidated alias, with a .md appended, into a path.join()-function which is read from the filesystem in the follow up routine and provides the pre-filled content of the new note. This allows an attacker to not only read arbitrary .md files from the filesystem, but also observes changes to them. The usefulness of this attack can be considered limited, since mainly markdown files are use the file-ending .md and all markdown files contained in the hedgedoc project, lik…

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2021-29474 has been found.
Attackers can target a specific entry point like noteController.showNote over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "CVE-2021-29474" on the vendor's site.

CVE-2021-29474
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: noteController.showNote
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) has been reported. Attackers reach the vulnerable code path via noteController.showNote without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions. Attack surface: noteController.showNote.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
Audit SBOM/dependencies for affected components.
```
資産台帳・SBOM・依存マニフェストで影響コンポーネントを特定する。
2
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

References

patch github.com