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Attacker controlled data in AST nodes is not validated (GHSL-2023-049)

Moderate
kivikakk published GHSA-5r3x-p7xx-x6q5 Mar 28, 2023

Package

cargo comrak (Rust)

Affected versions

< 0.17.0

Patched versions

0.17.0

Description

Impact

A Comrak AST can be constructed manually by a program instead of parsing a Markdown document with parse_document. This AST can then be converted to HTML via html::format_document_with_plugins. However, the HTML formatting code assumes that the AST is well-formed. For example, many AST notes contain [u8] fields which the formatting code assumes is valid UTF-8 data. Several bugs can be triggered if this is not the case.

Patches

0.17.0 contains adjustments to the AST, storing strings instead of unvalidated byte arrays.

Workarounds

  • Validate UTF-8 correctness of all data when assigning to &[u8] and Vec<u8> fields in the AST.

References

n/a

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVE ID

CVE-2023-28631

Weaknesses

No CWEs

Credits