wasmtime-wasi in Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 re-appends a trailing slash to rename source paths, causing renameat on macOS and FreeBSD hosts to follow directory symlinks. A guest with sandbox write access can rename a relative symlink such as "up/" to move host directories into its sandbox and read or write them.

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Fixes

Solution

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Workaround

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History

Wed, 28 Oct 2026 19:15:00 +0000

Type Values Removed Values Added
Description wasmtime-wasi in Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 re-appends a trailing slash to rename source paths, causing renameat on macOS and FreeBSD hosts to follow directory symlinks. A guest with sandbox write access can rename a relative symlink such as "up/" to move host directories into its sandbox and read or write them.
Title Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 Sandbox Escape via Symlink Rename
First Time appeared Bytecodealliance
Bytecodealliance wasmtime
Weaknesses CWE-61
CPEs cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:*
Vendors & Products Bytecodealliance
Bytecodealliance wasmtime
References
Metrics cvssV3_1

{'score': 7.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:L'}

cvssV4_0

{'score': 8.8, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-28T18:59:56.965Z

Reserved: 2026-10-28T17:31:29.498Z

Link: CVE-2026-118688

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-28T19:17:35.973

Modified: 2026-10-28T19:17:36.090

Link: CVE-2026-118688

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses