CVE-2023-50711 is a medium-severity (CVSS 5.7) Out-of-bounds Write vulnerability in vmm-sys-util. A fix is available for vmm-sys-util — see the affected versions and patch details below.
`serde` deserialization for `FamStructWrapper` lacks bound checks that could potentially lead to out-of-bounds memory access
Exploitation Status
No confirmed exploitation observed yet
- 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-2023-50711.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-50711 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
vmm-sys-utilReal-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
vmm-sys-util is a collection of modules that provides helpers and utilities used by multiple rust-vmm components. Starting in version 0.5.0 and prior to version 0.12.0, an issue in the FamStructWrapper::deserialize implementation provided by the crate for vmm_sys_util::fam::FamStructWrapper can lead to out of bounds memory accesses. The deserialization does not check that the length stored in the header matches the flexible array length. Mismatch in the lengths might allow out of bounds memory access through Rust-safe methods. The issue was corrected in version 0.12.0 by inserting a check that verifies the lengths of compared flexible arrays are equal for any deserialized header and aborting deserialization otherwise. Moreover, the API was changed so that header length can only be modified through Rust-unsafe code. This ensures that users cannot trigger out-of-bounds memory access from Rust-safe code.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | vmm-sys-util | ≥ 0.5.0&&< 0.12.0 | 0.12.0cargo update -p vmm-sys-util --precise 0.12.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vmm-sys-util, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update vmm-sys-util to 0.12.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-50711 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-50711 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-50711. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-50711 in your dependencies?
O3 Security finds CVE-2023-50711 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.