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MEDIUM

CVE-2021-29474

CVE-2021-29474 — Relative Path Traversal Attack on note creation

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…

Published Updated Sources: cvelistV5, GitHub_M

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

2%

chance of exploitation in 30 days

Affects

hedgedoc

hedgedoc

CVSS base

4.7

MEDIUM

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

hedgedoc

Products (1)

hedgedoc

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
4.7CVSS 3.1MEDIUM——cvelistV5

Weakness & attack patterns

  • CWE-20
  • CWE-22

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

  • T1562.003Impair Defenses: Impair Command History Logging
  • T1574.006Hijack Execution Flow: Dynamic Linker Hijacking
  • T1574.007Hijack Execution Flow: Path Interception by PATH Environment Variable

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Search application, proxy, and WAF logs for requests touching //localhost:3000/..%2F..%2FREADME#, //localhost:3000, //demo.hedgedoc.org/..%2F..%2FREADME#, /alias.

References

1 on the record

Elsewhere on this site

  • hedgedocevery CVE for this vendor
  • CWE-20other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.