CVE-2026-44216: Wasmtime Wasmtime Has A Panic When Vulnerability

MODERATE
Advisory Identifier: GHSA-p8xm-42r7-89xg
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CWE-770
Published
Advisory Summary

CVE-2026-44216 is a MODERATE wasmtime has a panic when vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Wasmtime libraries in the crates.io ecosystem. The issue involves wasmtime has a panic when allocating a table exceeding the size of the host's address space. Remediation is available by upgrading affected packages to version 36.0.8, 43.0.2.

CVE-2026-44216 at a Glance

CVE Identifier CVE-2026-44216
GHSA Identifier GHSA-p8xm-42r7-89xg
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product Wasmtime
Package Ecosystem crates.io
Published Date
Last Updated

How to Fix CVE-2026-44216

To remediate this vulnerability, upgrade all affected Wasmtime dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

wasmtime fixed: 36.0.8 
Upgrade wasmtime to 36.0.8
wasmtime fixed: 43.0.2 
Upgrade wasmtime to 43.0.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for wasmtime

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-44216, inspect your project dependencies for Wasmtime:

inspect dependencies for wasmtime

Analyze the terminal output to locate any version of Wasmtime in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 36.0.8), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In Wasmtime, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact Wasmtime's allocation logic for a WebAssembly table contained checked arithmetic which panicked on overflow. This overflow is possible to trigger, and thus panic, when a table with an extremely large size is allocated. This is possible with the WebAssembly memory64 proposal where tables can have sizes in the 64-bit range as opposed to the previous 32-bit range which would not overflow. The panic happens when attempting to create a very large table, such as when instantiating a WebAssembly module or component. This bug does not affect the pooling allocator which limits tables sizes to much less than the required amount to trigger the overflow. This bug is only present for the on-demand instance allocator, which is Wasmtime's default allocator. This bug also requires the `memory64` WebAssembly feature to be enabled, which is on-by-default. Panicking in the host process is considered a denial-of-service vector for Wasmtime. ### Patches Wasmtime 36.0.8, 43.0.2, and 44.0.1 have all been released which fixes this issue. ### Workarounds Embeddings can switch to using the pooling allocator to work around this issue, or the `memory64` WebAssembly proposal can be disabled. Otherwise there is no workaround and users are recommended to upgrade.

CVE-2026-44216 Affected Wasmtime Versions

2 component(s)
Fixed Versions:
36.0.843.0.2
Product / Package Ecosystem Affected Versions Fixed Version
wasmtime
 crates.io
≥ 30.0.0
< 36.0.8
36.0.8
wasmtime
 crates.io
≥ 37.0.0
< 43.0.2
43.0.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-p8xm-42r7-89xg
NVD — CVE-2026-44216 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-44216
Wasmtime Source Repository REPOSITORY
https://github.com/bytecodealliance/wasmtime
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2026-0114.html

Frequently Asked Questions

What is CVE-2026-44216?
CVE-2026-44216 is a security vulnerability in Wasmtime involving wasmtime has a panic when allocating a table exceeding the size of the host's address space under CWE-770: Allocation of Resources Without Limits or Throttling.
Which Wasmtime versions are affected?
Affected versions include releases prior to 36.0.8, 43.0.2 across affected packages: wasmtime.
What version fixes CVE-2026-44216?
Upgrading to 36.0.8, 43.0.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is wasmtime affected?
Yes, wasmtime is affected in releases prior to 36.0.8, 43.0.2. Upgrade your dependency to 36.0.8, 43.0.2 or later.
What CWE is associated with CVE-2026-44216?
CVE-2026-44216 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check crates.io dependencies for CVE-2026-44216?
Run the dependency tree command: 'inspect dependencies for wasmtime'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-p8xm-42r7-89xg",
  "modified" : "2026-05-14T20:49:47Z",
  "published" : "2026-05-07T00:08:59Z",
  "aliases" : [ "CVE-2026-44216" ],
  "summary" : "wasmtime has a panic when allocating a table exceeding the size of the host's address space",
  "details" : "### Impact\n\nWasmtime's allocation logic for a WebAssembly table contained checked arithmetic which panicked on overflow. This overflow is possible to trigger, and thus panic, when a table with an extremely large size is allocated. This is possible with the WebAssembly memory64 proposal where tables can have sizes in the 64-bit range as opposed to the previous 32-bit range which would not overflow. The panic happens when attempting to create a very large table, such as when instantiating a WebAssembly module or component.\n\nThis bug does not affect the pooling allocator which limits tables sizes to much less than the required amount to trigger the overflow. This bug is only present for the on-demand instance allocator, which is Wasmtime's default allocator. This bug also requires the `memory64` WebAssembly feature to be enabled, which is on-by-default.\n\nPanicking in the host process is considered a denial-of-service vector for Wasmtime.\n\n### Patches\n\nWasmtime 36.0.8, 43.0.2, and 44.0.1 have all been released which fixes this issue.\n\n### Workarounds\n\nEmbeddings can switch to using the pooling allocator to work around this issue, or the `memory64` WebAssembly proposal can be disabled. Otherwise there is no workaround and users are recommended to upgrade.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "wasmtime"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "30.0.0"
      }, {
        "fixed" : "36.0.8"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "wasmtime"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "37.0.0"
      }, {
        "fixed" : "43.0.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-p8xm-42r7-89xg"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-44216"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/bytecodealliance/wasmtime"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2026-0114.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-07T00:08:59Z",
    "nvd_published_at" : "2026-05-14T15:16:47Z"
  }
}