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os_str_bytes relies on undefined behavior of `char::from_u32_unchecked`

High severity GitHub Reviewed Published Aug 25, 2021 to the GitHub Advisory Database • Updated Jun 13, 2023

Package

cargo os_str_bytes (Rust)

Affected versions

< 2.0.0

Patched versions

2.0.0

Description

The Windows implementation of this crate relied on the behavior of std::char::from_u32_unchecked when its safety clause is violated. Even though this worked with Rust versions up to 1.42 (at least), that behavior could change with any new Rust version, possibly leading a security issue.

The flaw was corrected in version 2.0.0.

References

Published by the National Vulnerability Database Dec 31, 2020
Reviewed Aug 19, 2021
Published to the GitHub Advisory Database Aug 25, 2021
Last updated Jun 13, 2023

Severity

High

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
High

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:H

EPSS score

0.103%
(43rd percentile)

Weaknesses

CVE ID

CVE-2020-35865

GHSA ID

GHSA-q948-x8rf-888m

Source code

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