How severe is GHSA-gwc9-348x-qwv2?

GHSA-gwc9-348x-qwv2 has a CVSS score of 8.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-gwc9-348x-qwv2?

GHSA-gwc9-348x-qwv2 affects the following packages: wasmtime (crates.io), wasmtime (crates.io). Ecosystems affected: crates.io.

How do I fix GHSA-gwc9-348x-qwv2?

Update wasmtime to 0.34.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-gwc9-348x-qwv2 is resolved across your whole dependency graph.

How do I detect GHSA-gwc9-348x-qwv2 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for wasmtime. 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-gwc9-348x-qwv2 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-gwc9-348x-qwv2?

O3 pinpoints whether GHSA-gwc9-348x-qwv2 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-gwc9-348x-qwv2 actively exploited in the wild?

No public exploit code has been indexed for GHSA-gwc9-348x-qwv2 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-gwc9-348x-qwv2?

GHSA-gwc9-348x-qwv2 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 62th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-gwc9-348x-qwv2?

GHSA-gwc9-348x-qwv2 is classified as Use After Free (CWE-416). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-gwc9-348x-qwv2 published, and has it been updated?

GHSA-gwc9-348x-qwv2 was published on April 1, 2022 and was last updated on May 2, 2025. 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-gwc9-348x-qwv2

HIGH

Use after free in Wasmtime

Also known asCVE-2022-24791RUSTSEC-2022-0016RUSTSEC-2022-0099

Published

Apr 1, 2022

Updated

May 2, 2025

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk62th percentile+0.67%

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.

Blast Radius

2 pkgs affected

🦀wasmtime🦀wasmtime

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

There is a use after free vulnerability in Wasmtime when both running Wasm that uses externrefs and enabling epoch interruption in Wasmtime. If you are not explicitly enabling epoch interruption (it is disabled by default) then you are not affected. If you are explicitly disabling the Wasm reference types proposal (it is enabled by default) then you are also not affected.

The use after free is caused by Cranelift failing to emit stack maps when there are safepoints inside cold blocks. Cold blocks occur when epoch interruption is enabled. Cold blocks are emitted at the end of compiled functions, and change the order blocks are emitted versus defined. This reordering accidentally caused Cranelift to skip emitting some stack maps because it expected to emit the stack maps in block definition order, rather than block emission order. When Wasmtime would eventually collect garbage, it would fail to find live references on the stack because of the missing stack maps, think that they were unreferenced garbage, and therefore reclaim them. Then after the collection ended, the Wasm code could use the reclaimed-too-early references, which is a use after free.

This bug was discovered while extending our fuzz targets for externrefs and GC in Wasmtime. The updated fuzz target thoroughly exercises these code paths and feature combinations now. We have also added a regression test for this bug. Released versions 0.34.2 and 0.35.2, which fix the vulnerability. We recommend all Wasmtime users upgrade to these patched versions. If upgrading is not an option for you at this time, you can avoid the vulnerability by either disabling the Wasm reference types proposal or by disabling epoch interruption if you were previously enabling it.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`wasmtime`	all versions	0.34.2
🦀crates.io	`wasmtime`	≥ 0.35.0&&< 0.35.2	0.35.2

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for wasmtime. 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 to 0.34.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-gwc9-348x-qwv2 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-gwc9-348x-qwv2 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-gwc9-348x-qwv2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

There is a use after free vulnerability in Wasmtime when both running Wasm that uses `externref`s and enabling [epoch interruption](https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.epoch_interruption) in Wasmtime. If you are not explicitly enabling epoch interruption (it is disabled by default) then you are not affected. If you are explicitly disabling the Wasm reference types proposal (it is enabled by default) then you are also not affected. The use after free is caused by Cranelift failing to emit stack maps when there are safepoints inside cold blocks. Cold blocks occur

O3 Security · Impact-Aware SCA

Is GHSA-gwc9-348x-qwv2 in your dependencies?

O3 detects GHSA-gwc9-348x-qwv2 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.

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