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Incorrect check on buffer length in rand_core

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

Package

cargo rand_core (Rust)

Affected versions

>= 0.6.0, < 0.6.2

Patched versions

0.6.2

Description

An issue was discovered in the rand_core crate before 0.6.2 for Rust. Because read_u32_into and read_u64_into mishandle certain buffer-length checks, a random number generator may be seeded with too little data. The vulnerability was introduced in v0.6.0. The advisory doesn't apply to earlier minor version numbers.

Because read_u32_into and read_u64_into mishandle certain buffer-length checks, a random number generator may be seeded with too little data.

References

Published by the National Vulnerability Database Feb 18, 2021
Reviewed Aug 19, 2021
Published to the GitHub Advisory Database Aug 25, 2021
Last updated Jun 13, 2023

Severity

Critical

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
High
Integrity
High
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:H/I:H/A:H

EPSS score

0.214%
(59th percentile)

Weaknesses

CVE ID

CVE-2021-27378

GHSA ID

GHSA-w7j2-35mf-95p7

Source code

Credits

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