CVE-2021-29475
An attacker is able to receive arbitrary files from the file system when exporting a note to PDF.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.16%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 10.0 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
- EPSS
- 1.16% probability · 65th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-94, CWE-918
- Affected
- hedgedoc/hedgedoc
- Source
- security-advisories@github.com
References
- https://github.com/hedgedoc/hedgedoc/commit/c1789474020a6d668d616464cb2da5e90e123f65Patch, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-pxxg-px9v-6qf3Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/commit/c1789474020a6d668d616464cb2da5e90e123f65Patch, Third Party Advisory
- https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-pxxg-px9v-6qf3Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.