CVE-2026-118688

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.

Score

CVSS 4.0 8.8 High

Status

Deferred - disclosure@vulncheck.com

Published

2026-10-28

Last modified

2026-10-28

Weaknesses

CWE-61

Affected products

• Wasmtime (Bytecodealliance)

References

• https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m9f7-9w4p-gv38
• https://www.vulncheck.com/advisories/wasmtime-before-36.0.18-37.0.0-before-48.0.6-and-49.0.0-before-49.0.3-sandbox-esca…