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No exploitation reportedFix available

CVE-2021-29475

No exploitation reported by the sources we read.

  • Published2021-04-26
  • Fixed in1.5.0
  • WeaknessCWE-918 · CWE-94

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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 JavaScript rendering. The impact is pretty bad, as the attacker is able to read the CodiMD/HedgeDoc `config.json` file as well any other files on the filesystem. Even though the suggested Docker deploy option doesn't have many interesting files itself, the `config.json` still often contains sensitive information, database credentials, and maybe OAuth secrets among other things.

Timeline

dates in UTC
  1. 2021-04-2619:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-29475?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-29475?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Hedgedoc
BranchAffectedFixed in
1.5< 1.5.01.5.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Hedgedoc to 1.5.0

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CNACVSS 3.110read 2026-10-23
  • NVDCVSS 3.110read 2026-10-23
  • NVDCVSS 2.05.8read 2026-10-23
  • CNAweakness (CWE)CWE-918, CWE-94read 2026-10-23
  • NVDweakness (CWE)CWE-918, CWE-94read 2026-10-23
  • FIRST EPSSEPSS score1.2 %2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
Published
2021-04-26
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-29475?

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 JavaScript rendering. The impact is pretty bad, as the attacker is able to read the CodiMD/HedgeDoc `config.json` file as well any other files on the filesystem. Even though the suggested Docker deploy option doesn't have many interesting files itself, the `config.json` still often contains sensitive information, database credentials, and maybe OAuth secrets among other things.

Is CVE-2021-29475 actively exploited?

Active exploitation of CVE-2021-29475 has not been confirmed. Its EPSS score was 1.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-29475?

CVE-2021-29475 has a CVSS v3 base score of 10 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N.

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