Bytecode Alliance Wasmtime up to 36.0.17/48.0.5/49.0.2 wasmtime-wasi sandbox

Summaryinfo

A vulnerability classified as critical has been found in Bytecode Alliance Wasmtime up to 36.0.17/48.0.5/49.0.2. This affects an unknown function of the component wasmtime-wasi. This manipulation causes sandbox. This vulnerability is handled as CVE-2026-118688. The attack can be initiated remotely. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Bytecode Alliance Wasmtime up to 36.0.17/48.0.5/49.0.2 and classified as critical. Affected by this vulnerability is some unknown processing of the component wasmtime-wasi. The manipulation with an unknown input leads to a sandbox vulnerability. The CWE definition for the vulnerability is CWE-265. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-118688 since 10/28/2026. The exploitation appears to be easy. The attack can be launched remotely. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1611 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 373450 (Linux Distros Unpatched Vulnerability : CVE-2026-118688), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 36.0.18, 48.0.6 or 49.0.3 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (373450). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• Bytecode Alliance

Name

• Wasmtime

Version

• 36.0.0
• 36.0.1
• 36.0.2
• 36.0.3
• 36.0.4
• 36.0.5
• 36.0.6
• 36.0.7
• 36.0.8
• 36.0.9
• 36.0.10
• 36.0.11
• 36.0.12
• 36.0.13
• 36.0.14
• 36.0.15
• 36.0.16
• 36.0.17
• 48.0.0
• 48.0.1
• 48.0.2
• 48.0.3
• 48.0.4
• 48.0.5
• 49.0.0
• 49.0.1
• 49.0.2

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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