CVE-2024-38358: Symlink bypasses filesystem sandbox in wasmer

Severity: low (CVSS 2.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-06-19 · updated 2026-06-17
Weakness: CWE-22

Description

Wasmer is a web assembly (wasm) Runtime supporting WASIX, WASI and Emscripten. If the preopened directory has a symlink pointing outside, WASI programs can traverse the symlink and access host filesystem if the caller sets both `oflags::creat` and `rights::fd_write`. Programs can also crash the runtime by creating a symlink pointing outside with `path_symlink` and `path_open`ing the link. This issue has been addressed in commit `b9483d022` which has been included in release version 4.3.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Affected products

wasmerio wasmer: before 4.3.2 — fixed in 4.3.2

How to fix

Upgrade to a fixed version: wasmerio wasmer 4.3.2. Check the vendor advisory for mitigations.

References

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