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Vulnerabilities

Security incident · CVE-2025-61670

Wasmtime is a runtime for WebAssembly.

Published Oct 7, 2025 · catalog updated Oct 7, 2025 · Wasmtime is a runtime

Last checked Nov 5, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-61670. EPSS is 0.19%. Act only if a listed version of Wasmtime is a runtime is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Wasmtime is a runtime).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Low1.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.19%
Remediation
Version ranges on file
Affected products
vendor bytecodealliance wasmtime 37.0.0, < 37.0.2

Wasmtime is a runtime for WebAssembly. Wasmtime 37.0.0 and 37.0.1 have memory leaks in the C/C++ API when using bindings for the or WebAssembly values. This is caused by a regression introduced during the development of 37.0.0 and all prior versions of Wasmtime are unaffected. If or is not used in the C/C++ API then embeddings are also unaffected by the leaky behavior. The Rust crate is unaffected by this leak. Development of Wasmtime 37.0.0 included a refactoring in Rust of changing the old type to a new type. This change was integrated into Wasmtime's C API but left the C API in a state whic

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor bytecodealliance wasmtime 37.0.0, < 37.0.237.0.0, < 37.0.2

How to fix CVE-2025-61670

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-61670. EPSS is 0.19%. Act only if a listed version of Wasmtime is a runtime is installed.

Which versions are affected?

Compare what you have installed with bytecodealliance wasmtime 37.0.0, < 37.0.2 37.0.0, < 37.0.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.19%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 7, 2025 · EUVD

    Detected

    Wasmtime is a runtime for WebAssembly. Wasmtime 37.0.0 and 37.0.1 have memory leaks in the C/C++ API when using bindings for the or WebAssembly values. This is caused by a regression introduced during the development of 37.0.0 and all prior versions of Wasmtime are unaffected. If or is not used in the C/C++ API then embeddings are also unaffected by the leaky behavior. The Rust crate is unaffected

  2. Oct 7, 2025 · EUVD

    Updated

    Wasmtime is a runtime for WebAssembly. Wasmtime 37.0.0 and 37.0.1 have memory leaks in the C/C++ API when using bindings for the or WebAssembly values. This is caused by a regression introduced during the development of 37.0.0 and all prior versions of Wasmtime are unaffected. If or is not used in the C/C++ API then embeddings are also unaffected by the leaky behavior. The Rust crate is unaffected

Sources

  • CVE.orgVulnerability recordCVE-2025-61670

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-61670

    30-day exploitation probability 0.19%

    first.org
  • EUVDVulnerability recordEUVD-2025-33183

    Wasmtime is a runtime for WebAssembly. Wasmtime 37.0.0 and 37.0.1 have memory leaks in the C/C++ API when using bindings for the or WebAssembly values. This is caused by a regression introduced during the development of 37.0.0 and all prior versions of Wasmtime are unaffected. If

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 5, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 5, 2026
  • CVE.orgOct 23, 2026
  • EUVDOct 23, 2026