# CVE-2026-44216: Bytecode Alliance Wasmtime denial of service via table allocation panic

Source: https://junglewise.ai/threats/cve-2026-44216-bytecode-alliance-wasmtime-denial-of-service-via-table-allocation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-14. Updated: 2026-05-18  
License: CC BY 4.0 with a link back

CVE-2026-44216 · Severity: high · CVSS 7.5 · Published 2026-05-14

Wasmtime is a runtime used to execute WebAssembly code, often used to run untrusted code safely in isolated environments. A flaw in how it handles memory allocation for very large data tables can cause the entire host application to crash. This allows a user with the ability to provide WebAssembly modules to trigger a denial-of-service, potentially disrupting services or applications relying on the runtime.

Technologies: [wasmtime (crates.io)](https://junglewise.ai/threats/technologies/wasmtime). Vendors: [crates.io](https://junglewise.ai/threats/vendors/crates-io).

## Quick answers

**Is CVE-2026-44216 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-44216 being exploited in the wild.

**How severe is CVE-2026-44216?** High severity, with a CVSS score of 7.5, published 14 May 2026.

**Which products and versions are affected?** wasmtime (crates.io) SEMVER:introduced=30.0.0,fixed=36.0.8, SEMVER:introduced=30.0.0,fixed=36.0.8,introduced=37.0.0,fixed=43.0.2,introduced=44.0.0,fixed=44.0.1.

**Is there a fix for CVE-2026-44216?** Yes. wasmtime (crates.io): upgrade to 36.0.8, 44.0.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-44216 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-44216?** Check whether you run wasmtime (crates.io) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- wasmtime (crates.io): upgrade to 36.0.8, 44.0.1 or later

  ```sh
  cargo update -p wasmtime
  ```


## Technical details

Wasmtime's on-demand instance allocator contains a vulnerability in its table allocation logic where checked arithmetic can result in a panic upon overflow. This is specifically exploitable when the 'memory64' WebAssembly proposal is enabled (which is the default), as it allows for 64-bit table sizes that can exceed the host's address space and trigger the overflow. An attacker who can provide a malicious WebAssembly module or component can trigger this panic during instantiation, leading to a denial-of-service of the host process. The pooling allocator is not affected as it enforces stricter limits on table sizes. The issue is resolved in versions 36.0.8, 43.0.2, and 44.0.1.

## Affected products

- Bytecode Alliance Wasmtime 30.0.0 to 36.0.7, 37.0.0 to 43.0.1, 44.0.0

## Identifiers

- CVE-2026-44216
- GHSA-p8xm-42r7-89xg
- RUSTSEC-2026-0114

## Timeline

- 2026-04-30: advisory: GitHub advisory published by maintainers
- 2026-05-14: disclosed: CVE published to NVD

## References

- [https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-p8xm-42r7-89xg](https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-p8xm-42r7-89xg)

## Related threats

- [RUSTSEC-2026-0422 - Typed functions with `i31` or `nullref` arguments may panic due to insufficient type-check](https://junglewise.ai/threats/rustsec-2026-0422-typed-functions-with-i31-or-nullref-arguments-may-0545dc2b)
- [Wasmtime type confusion with host-created struct types](https://junglewise.ai/threats/rustsec-2026-0423-cross-engine-type-confusion-with-host-created-struct-89fe3f0e)
- [Wasmtime unchecked memory usage in borrowed resource transfer](https://junglewise.ai/threats/rustsec-2026-0424-unchecked-memory-usage-in-transferring-borrowed-b297503c)
- [Wasmtime Cranelift aarch64 br_table sandbox escape](https://junglewise.ai/threats/cve-2026-115893-wasmtime-is-a-runtime-for-webassembly-prior-to-36-0-19-48-0-7)
- [Wasmtime component-model type-check bypass in stream/future lowering](https://junglewise.ai/threats/cve-2026-115892-wasmtime-is-a-runtime-for-webassembly-from-46-0-0-until-48-0-7)