CVE Intelligence
Skip to main content
CRITICAL

CVE-2021-29475

CVE-2021-29475 — PDF export allows arbitrary file reads

HedgeDoc (formerly known as CodiMD) is an open-source collaborative markdown editor. An attacker is able to receive arbitrary files from the file system when exporting a note to PDF. Since the code injection has to take place as note content, there fore this exploit requires the attackers ability to modify a note. This will affect all instances, which have pdf export enabled. This issue has been fixed by https://github.com/hedgedoc/hedgedoc/commit/c1789474020a6d668d616464cb2da5e90e123f65 and is available in version 1.5.0. Starting the CodiMD/HedgeDoc instance with `CMD_ALLOW_PDF_EXPORT=false` or set `"allowPDFExport": false` in config.json can mitigate this issue for those who cannot upgrade. This exploit works because while PhantomJS doesn't actually render the `file:///` references to the PDF file itself, it still uses them internally, and exfiltration is possible, and easy through…

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

1%

chance of exploitation in 30 days

Affects

hedgedoc

hedgedoc

CVSS base

10

CRITICAL

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
10CVSS 3.1CRITICAL——cvelistV5

Weakness & attack patterns

  • CWE-94
  • CWE-918

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

  • T1027.006Obfuscated Files or Information: HTML Smuggling
  • T1027.009Obfuscated Files or Information: Embedded Payloads
  • T1564.009Hide Artifacts: Resource Forking

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 //github.com/hedgedoc/hedgedoc/commit/c1789474020a6d668d616464cb2da5e90e123f65, /HedgeDoc, ///.

References

2 on the record

Elsewhere on this site

  • hedgedocevery CVE for this vendor
  • CWE-94other 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.