Out-of-bounds Read Affecting wasmcloud package, versions <2.0.4-r0


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.02% (5th percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-WASMCLOUD-16122125
  • published22 Apr 2026
  • disclosed9 Apr 2026

Introduced: 9 Apr 2026

NewCVE-2026-34941  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

Upgrade Chainguard wasmcloud to version 2.0.4-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream wasmcloud package and not the wasmcloud package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a vulnerability where when transcoding a UTF-16 string to the latin1+utf16 component-model encoding it would incorrectly validate the byte length of the input string when performing a bounds check. Specifically the number of code units were checked instead of the byte length, which is twice the size of the code units. This vulnerability can cause the host to read beyond the end of a WebAssembly's linear memory in an attempt to transcode nonexistent bytes. In Wasmtime's default configuration this will read unmapped memory on a guard page, terminating the process with a segfault. Wasmtime can be configured, however, without guard pages which would mean that host memory beyond the end of linear memory may be read and interpreted as UTF-16. A host segfault is a denial-of-service vulnerability in Wasmtime, and possibly being able to read beyond the end of linear memory is additionally a vulnerability. Note that reading beyond the end of linear memory requires nonstandard configuration of Wasmtime, specifically with guard pages disabled. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.

CVSS Base Scores

version 3.1