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Use after free in Rocket

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

Package

cargo rocket (Rust)

Affected versions

< 0.4.7

Patched versions

0.4.7

Description

Affected versions of this crate transmuted a &str to a &'static str before pushing it into a StackVec, this value was then popped later in the same function.

This was assumed to be safe because the reference would be valid while the method's stack was active. In between the push and the pop, however, a function f was called that could invoke a user provided function.

If the user provided panicked, then the assumption used by the function was no longer true and the transmute to &'static would create an illegal static reference to the string. This could result in a freed string being used during (such as in a Drop implementation) or after (e.g through catch_unwind) the panic unwinding.

This flaw was corrected in commit e325e2f by using a guard object to ensure that the &'static str was dropped inside the function.

References

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
Low
Integrity
Low
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:L/I:L/A:L

EPSS score

0.131%
(49th percentile)

Weaknesses

CVE ID

CVE-2021-29935

GHSA ID

GHSA-vcw4-8ph6-7vw8

Source code

Credits

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