CVE-2023-35936

Arbitrary file write is possible in Pandoc when using PDF output or --extract-media with untrusted input

Published Jul 5, 2023 CVSS 3.1 · 6 Medium EPSS < 1% KEV · Not listed
Description
Pandoc is a Haskell library for converting from one markup format to another, and a command-line tool that uses this library. Starting in version 1.13 and prior to version 3.1.4, Pandoc is susceptible to an arbitrary file write vulnerability, which can be triggered by providing a specially crafted image element in the input when generating files using the `--extract-media` option or outputting to PDF format. This vulnerability allows an attacker to create or overwrite arbitrary files on the system ,depending on the privileges of the process running pandoc. It only affects systems that pass untrusted user input to pandoc and allow pandoc to be used to produce a PDF or with the `--extract-media` option.

The fix is to unescape the percent-encoding prior to checking that the resource is not above the working directory, and prior to extracting the extension. Some code for checking that the path is below the working directory was flawed in a similar way and has also been fixed. Note that the `--sandbox` option, which only affects IO done by readers and writers themselves, does not block this vulnerability. The vulnerability is patched in pandoc 3.1.4. As a workaround, audit the pandoc command and disallow PDF output and the `--extract-media` option.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-3507-1 pandoc security update
EUVD EUVD EUVD-2023-39920 Pandoc is a Haskell library for converting from one markup format to another, and a command-line tool that uses this library. Starting in version 1.13 and prior to version 3.1.4, Pandoc is susceptible to an arbitrary file write vulnerability, which can be triggered by providing a specially crafted image element in the input when generating files using the `--extract-media` option or outputting to PDF format. This vulnerability allows an attacker to create or overwrite arbitrary files on the system ,depending on the privileges of the process running pandoc. It only affects systems that pass untrusted user input to pandoc and allow pandoc to be used to produce a PDF or with the `--extract-media` option. The fix is to unescape the percent-encoding prior to checking that the resource is not above the working directory, and prior to extracting the extension. Some code for checking that the path is below the working directory was flawed in a similar way and has also been fixed. Note that the `--sandbox` option, which only affects IO done by readers and writers themselves, does not block this vulnerability. The vulnerability is patched in pandoc 3.1.4. As a workaround, audit the pandoc command and disallow PDF output and the `--extract-media` option.
History
Type Values Removed Values Added
Description Pandoc is a Haskell library for converting from one markup format to another, and a command-line tool that uses this library. Starting in version 1.13 and prior to version 3.1.4, Pandoc is susceptible to an arbitrary file write vulnerability, which can be triggered by providing a specially crafted image element in the input when generating files using the `--extract-media` option or outputting to PDF format. This vulnerability allows an attacker to create or overwrite arbitrary files on the system ,depending on the privileges of the process running pandoc. It only affects systems that pass untrusted user input to pandoc and allow pandoc to be used to produce a PDF or with the `--extract-media` option. The fix is to unescape the percent-encoding prior to checking that the resource is not above the working directory, and prior to extracting the extension. Some code for checking that the path is below the working directory was flawed in a similar way and has also been fixed. Note that the `--sandbox` option, which only affects IO done by readers and writers themselves, does not block this vulnerability. The vulnerability is patched in pandoc 3.1.4. As a workaround, audit the pandoc command and disallow PDF output and the `--extract-media` option. Pandoc is a Haskell library for converting from one markup format to another, and a command-line tool that uses this library. Starting in version 1.13 and prior to version 3.1.4, Pandoc is susceptible to an arbitrary file write vulnerability, which can be triggered by providing a specially crafted image element in the input when generating files using the `--extract-media` option or outputting to PDF format. This vulnerability allows an attacker to create or overwrite arbitrary files on the system ,depending on the privileges of the process running pandoc. It only affects systems that pass untrusted user input to pandoc and allow pandoc to be used to produce a PDF or with the `--extract-media` option. The fix is to unescape the percent-encoding prior to checking that the resource is not above the working directory, and prior to extracting the extension. Some code for checking that the path is below the working directory was flawed in a similar way and has also been fixed. Note that the `--sandbox` option, which only affects IO done by readers and writers themselves, does not block this vulnerability. The vulnerability is patched in pandoc 3.1.4. As a workaround, audit the pandoc command and disallow PDF output and the `--extract-media` option.
Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Feb 13, 2025, 4:55 PM
Reserved
Jun 20, 2023, 2:02 PM
Status
Modified
Published
Jul 5, 2023, 9:15 PM
Modified
Jun 17, 2026, 6:05 AM
Severity
Moderate
Public date
Jul 6, 2023, 12:00 AM