🛡️ CVE-2021-29935 — rocket

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-416 OSV
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Use after free in Rocket

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity low, availability low.

Weakness class

CVE-2021-29935 is classified as CWE-416: Use After Free. Memory is used after being released, so its contents may already belong to something else.

Affected software

CVE-2021-29935 is recorded against 1 package.

  • rocket

Timeline and source

Published on 25 August 2021 and last revised on 8 November 2023. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

nvd.nist.gov (Advisory)
github.com (Web)
github.com (Web)
github.com (Web)
github.com (Package)
rustsec.org (Web)

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CWE CWE-416
Public Exploit ✅ No
Source OSV
Published 2021-08-25
Updated 2026-08-12
Modified 2023-11-08
Fix URL N/A

Affected Packages

Software From version Fixed in
rocket — —

Similar Threats

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