Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not adequately account for host allocations when lifting guest values through the dynamically-typed Val API, bypassing the hostcall fuel limit. A malicious WebAssembly guest can return crafted values that allocate at least ~100x more host memory than tracked, causing denial of service.

Attack Vector Adjacent Network

Attack Complexity High

Privileges Required Low

Attack Requirements Present

User Interaction Passive

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Adjacent Network

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
bytecodealliance wasmtime unaffected
Version Status Constraints
0 affected < 36.0.16
36.0.16 unaffected —
37.0.0 affected < 48.0.3
48.0.3 unaffected —
49.0.0 affected < 49.0.1
49.0.1 unaffected —

No data.

No data.

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Project Subscriptions

Vendors Products
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Wasmtime Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jqpg-j7w6-42pr cve-icon cve-icon
https://www.vulncheck.com/advisories/wasmtime-before-36.0.16-37.0.0-before-48.0.3-and-49.0.0-before-49.0.1-denial-of-service-via-val-api cve-icon cve-icon
History

Fri, 23 Oct 2026 00:45:00 +0000

Type Values Removed Values Added
Description Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not adequately account for host allocations when lifting guest values through the dynamically-typed Val API, bypassing the hostcall fuel limit. A malicious WebAssembly guest can return crafted values that allocate at least ~100x more host memory than tracked, causing denial of service.
Title Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 Denial of Service via Val API
First Time appeared Bytecodealliance
Bytecodealliance wasmtime
Weaknesses CWE-770
CPEs cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:*
Vendors & Products Bytecodealliance
Bytecodealliance wasmtime
References
Metrics cvssV3_1

{'score': 2.3, 'vector': 'CVSS:3.1/AV:A/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L'}

cvssV4_0

{'score': 1, 'vector': 'CVSS:4.0/AV:A/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-22T19:13:55.163Z

Reserved: 2026-10-22T11:27:18.001Z

Link: CVE-2026-115389

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-22T19:17:46.330

Modified: 2026-10-22T19:17:46.453

Link: CVE-2026-115389

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-23T03:30:15Z

Weaknesses