CVE-2026-54786
5.0 · MEDIUMOverview
CVE-2026-54786 is a medium-severity vulnerability affecting bytecodealliance wasmtime. It was published on July 1, 2026 and has a CVSS 3.1 base score of 5.0 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.0, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
Wasmtime is a runtime for WebAssembly. All versions prior to 24.0.10; versions 25.0.0 through those before 36.0.11; versions 37.0.0 through those before 44.0.3; and versions 45.0.0 and 45.0.1 contain a native implementation of WASIp1 which 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. In a loop, guests can use fd_renumber to cause hosts to exhaust both resources and file descriptors. This bug only affects the native implementation of WASIp1, meaning that only runtimes which load core wasm modules and expose fd_renumber are affected. Runtimes are additionally only affe
Remediation
Check the references section for vendor advisories and patches from bytecodealliance. Update wasmtime to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| bytecodealliance | wasmtime | >= 0, < 24.0.10 | Affected |
Frequently Asked Questions
What is CVE-2026-54786?
CVE-2026-54786 is a medium-severity vulnerability affecting bytecodealliance wasmtime. It was published on July 1, 2026 and has a CVSS 3.1 base score of 5.0 (MEDIUM).
How severe is CVE-2026-54786?
This vulnerability has a CVSS 3.1 base score of 5.0, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-54786?
Check the references section for vendor advisories and patches from bytecodealliance. Update wasmtime to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-54786?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-54786 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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