CVE-2026-27195
Vulnerability Scoring
Status: Awaiting Analysis
Published on: 24 Feb 2026, 22:16 UTC
CVSS Release:
CVE-2026-27195: Wasmtime is a runtime for WebAssembly. Starting with Wasmtime 39.0.0, the `component-model-async` feature became the default, which brought with it a new implementation of `[Typed]Func::call_async` which made it capable of calling async-typed guest export functions. However, that implementation had a bug leading to a panic under certain circumstances: First, the host embedding calls `[Typed]Func::call_async` on a function exported by a component, polling the returned `Future` once. Second, the component function yields control to the async runtime (e.g. Tokio), e.g. due to a call to host function registered using `LinkerInstance::func_wrap_async` which yields, or due an epoch interruption. Third, the host embedding drops the `Future` after polling it once. This leaves the component instance in a non-reenterable state since the call never had a chance to complete. Fourth, the host embedding calls `[Typed]Func::call_async` again, polling the returned `Future`. Since the component instance cannot be entered at this point, the call traps, but not before allocating a task and thread for the call. Fifth, the host embedding ignores the trap and drops the `Future`. This panics due to the runtime attempting to dispose of the task created above, which panics since the thread has not yet exited. When a host embedder using the affected versions of Wasmtime calls `wasmtime::component::[Typed]Func::call_async` on a guest export and then drops the returned future without waiting for it to resolve, and then does so again with the same component instance, Wasmtime will panic. Embeddings that have the `component-model-async` compile-time feature disabled are unaffected. Wasmtime 40.0.4 and 41.0.4 have been patched to fix this issue. Versions 42.0.0 and later are not affected. If an embedding is not actually using any component-model-async features then disabling the `component-model-async` Cargo feature can work around this issue. This issue can also be worked around by either ensuring every `call_async` future is awaited until it completes or refraining from using the `Store` again after dropping a not-yet-resolved `call_async` future.
The exploitability of CVE-2026-27195 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
No exploitability data is available for CVE-2026-27195.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-27195, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-27195, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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