GHSA-3p27-qvp9-27qf is a medium-severity (CVSS 5) Uncontrolled Resource Consumption vulnerability in wasmtime-wasi. O3 Security confirms whether GHSA-3p27-qvp9-27qf is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Wasmtime has a leak in WASIp1 `fd_renumber` implementation
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
GHSA-3p27-qvp9-27qf 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 0 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
wasmtime-wasi🦀wasmtime-wasi🦀wasmtime-wasi🦀wasmtime-wasiReal-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
Impact
Wasmtime's native implementation of WASIp1 suffers from a leak in the fd_renumber function where the file descriptor being renumbered to is not properly closed. Wasmtime's implementation erroneously only updated the table of descriptors for WASIp1 and didn't update the underlying table of descriptors used by the host. This behavior means that while fd_renumber works correctly from a guest's perspective it ends up leaking resources in the host that aren't cleaned up until the corresponding Store is destroyed. This means that guests can, in a loop, use fd_renumber to cause hosts to exhaust resources or exhaust file descriptors.
This bug only affects the native implementation of WASIp1. This means that only runtimes which load core wasm modules and expose fd_renumber are affected. Runtimes are additionally only affected if they expose the ability to acquire a file descriptor, such as opening a file. For runtimes that deny access to files they are unaffected.
Patches
Wasmtime 24.0.10, 36.0.11, 44.0.3, and 45.0.2 have been released which fix this issue.
Workarounds
There are no workarounds for this issue and hosts are recommended to update.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | wasmtime-wasi | all versions | 24.0.10 |
| 🦀crates.io | wasmtime-wasi | ≥ 45.0.0&&< 45.0.2 | 45.0.2 |
| 🦀crates.io | wasmtime-wasi | ≥ 25.0.0&&< 36.0.11 | 36.0.11 |
| 🦀crates.io | wasmtime-wasi | ≥ 37.0.0&&< 44.0.3 | 44.0.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for wasmtime-wasi. 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 wasmtime-wasi to 24.0.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3p27-qvp9-27qf 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-3p27-qvp9-27qf 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-3p27-qvp9-27qf. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-3p27-qvp9-27qf in your dependencies?
O3 detects GHSA-3p27-qvp9-27qf 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.