CVE-2018-25023 is a high-severity (CVSS 7.5) CWE-908 vulnerability in smallvec. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for smallvec — see the affected versions and patch details below.
Use of Uninitialized Resource in smallvec
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2018-25023.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
smallvecReal-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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | smallvec | all versions | 0.6.13cargo update -p smallvec --precise 0.6.13 |
Affected Products
smallvecservoResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for smallvec, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update smallvec to 0.6.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-25023 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.
Frequently Asked Questions
Is CVE-2018-25023 in your dependencies?
Find it across crates.io, including transitive dependencies.