Instituto Nacional de ciberseguridad. Sección Incibe
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CVE-2026-27572

Severity CVSS v4.0:
MEDIUM
Type:
Unavailable / Other
Publication date:
24/02/2026
Last modified:
25/02/2026

Description

Wasmtime is a runtime for WebAssembly. Prior to versions 24.0.6, 36.0.6, 4.0.04, 41.0.4, and 42.0.0, Wasmtime's implementation of the `wasi:http/types.fields` resource is susceptible to panics when too many fields are added to the set of headers. Wasmtime's implementation in the `wasmtime-wasi-http` crate is backed by a data structure which panics when it reaches excessive capacity and this condition was not handled gracefully in Wasmtime. Panicking in a WASI implementation is a Denial of Service vector for embedders and is treated as a security vulnerability in Wasmtime. Wasmtime 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0 patch this vulnerability and return a trap to the guest instead of panicking. There are no known workarounds at this time. Embedders are encouraged to update to a patched version of Wasmtime.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H CVSS v4.0 Severity and Metrics:

Base Score: 6.90 MEDIUM
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): Present
Privileges Required (PR): Low
User Interaction (UI): Passsive
Confidentiality (VC): None
Integrity (VI): None
Availability (VA): High
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): High

Base Score 4.0
6.90
Severity 4.0
MEDIUM
Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS v3.1 Severity and Metrics:

Base Score: 7.50 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): High

Base Score 3.x
7.50
Severity 3.x
HIGH

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* 24.0.6 (excluding)
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* 25.0.0 (including) 36.0.6 (excluding)
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* 37.0.0 (including) 40.0.4 (excluding)
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* 41.0.0 (including) 41.0.4 (excluding)

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools