How severe is GHSA-66p5-j55p-32r9?

No CVSS score has been assigned to GHSA-66p5-j55p-32r9 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-66p5-j55p-32r9?

GHSA-66p5-j55p-32r9 affects the following packages: smallvec (crates.io). Ecosystems affected: crates.io.

How do I fix GHSA-66p5-j55p-32r9?

Update smallvec to 0.6.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-66p5-j55p-32r9 is resolved across your whole dependency graph.

How do I detect GHSA-66p5-j55p-32r9 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for smallvec. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-66p5-j55p-32r9 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-66p5-j55p-32r9?

O3 pinpoints whether GHSA-66p5-j55p-32r9 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-66p5-j55p-32r9 actively exploited in the wild?

Yes. There are 1 known exploit references for GHSA-66p5-j55p-32r9, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What type of vulnerability is GHSA-66p5-j55p-32r9?

GHSA-66p5-j55p-32r9 is classified as CWE-908 (CWE-908). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-66p5-j55p-32r9 published, and has it been updated?

GHSA-66p5-j55p-32r9 was published on August 25, 2021 and was last updated on November 8, 2023. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀 crates.io

GHSA-66p5-j55p-32r9

GHSA-66p5-j55p-32r9 is a CWE-908 vulnerability in smallvec. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-66p5-j55p-32r9 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

smallvec creates uninitialized value of any type

Also known asCVE-2018-25023 GHSA-55m5-whcv-c49cRUSTSEC-2018-0018

Published

Aug 25, 2021

Updated

Nov 8, 2023

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Blast Radius

1 pkg affected

🦀smallvec

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

Affected versions of this crate called mem::uninitialized() to create values of a user-supplied type T. This is unsound e.g. if T is a reference type (which must be non-null and thus may not remain uninitialized).

The flaw was corrected by avoiding the use of mem::uninitialized(), using MaybeUninit instead.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`smallvec`	all versions	0.6.13

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

An issue was discovered in the smallvec crate before 0.6.13 for Rust. It…

rustsec.orgNVDJan 2022

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for smallvec. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update smallvec to 0.6.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-66p5-j55p-32r9 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-66p5-j55p-32r9 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-66p5-j55p-32r9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Affected versions of this crate called `mem::uninitialized()` to create values of a user-supplied type `T`. This is unsound e.g. if `T` is a reference type (which must be non-null and thus may not remain uninitialized). The flaw was corrected by avoiding the use of `mem::uninitialized()`, using `MaybeUninit` instead.

O3 Security · Impact-Aware SCA

Is GHSA-66p5-j55p-32r9 in your dependencies?

O3 detects GHSA-66p5-j55p-32r9 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works