CVE-2023-51661
Filesystem sandbox not enforced in wasmer-cli
Wasmer is a WebAssembly runtime that enables containers to run anywhere: from Desktop to the Cloud, Edge and even the browser. Wasm programs can access the filesystem outside of the sandbox. Service providers running untrusted Wasm code on Wasmer can unexpectedly expose the host filesystem. This vulnerability has been patched in version 4.2.4.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Filesystem sandbox not enforced in wasmer-cli
Wasmer is a WebAssembly runtime that enables containers to run anywhere: from Desktop to the Cloud, Edge and even the browser. Wasm programs can access the filesystem outside of the sandbox. Service providers running untrusted Wasm code on Wasmer can unexpectedly expose the host filesystem. This vulnerability has been patched in version 4.2.4.
- Record
CVE-2023-51661- CVSS 3.1
- 8.4 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-284
- Updated
- 2026-11-02
EUVDEUVD-2023-3103
Wasmer is a WebAssembly runtime that enables containers to run anywhere: from Desktop to the Cloud, Edge and even the browser. Wasm programs can access the filesystem outside of the sandbox. Service providers running untrusted Wasm code on Wasmer can unexpectedly expose the host filesystem. This vulnerability has been patched in version 4.2.4.
- Record
EUVD-2023-3103- CVSS 3.1
- 8.4 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-4mq4-7rw3-vm5j
Wasmer filesystem sandbox not enforced
Summary
As of Wasmer version v4.2.3, Wasm programs can access the filesystem outside of the sandbox.
Details
https://github.com/wasmerio/wasmer/issues/4267
PoC
A minimal Rust program:
fn main() {
let f = std::fs::OpenOptions::new()
.write(true)
.create_new(true)
.open("abc")
.unwrap();
}
This should be compiled with cargo build --target wasm32-wasi. The compiled program, when run with wasmer WITHOUT --dir, can still create a file in the working directory.
Impact
Service providers running untrusted Wasm code on Wasmer can unexpectedly expose the host filesystem.
- Record
GHSA-4mq4-7rw3-vm5j- CVSS 3.1
- 8.4 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-284
- Updated
- 2026-11-02
NVD
Wasmer is a WebAssembly runtime that enables containers to run anywhere: from Desktop to the Cloud, Edge and even the browser. Wasm programs can access the filesystem outside of the sandbox. Service providers running untrusted Wasm code on Wasmer can unexpectedly expose the host filesystem. This vulnerability has been patched in version 4.2.4.
- Record
CVE-2023-51661- CVSS 3.1
- 8.4 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-284
- Updated
- 2026-11-02
OSV
Filesystem sandbox not enforced in wasmer-cli
Wasmer is a WebAssembly runtime that enables containers to run anywhere: from Desktop to the Cloud, Edge and even the browser. Wasm programs can access the filesystem outside of the sandbox. Service providers running untrusted Wasm code on Wasmer can unexpectedly expose the host filesystem. This vulnerability has been patched in version 4.2.4.
- Record
CVE-2023-51661- CVSS 3.1
- 8.4 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-284
- Updated
- 2026-11-02
OSVGHSA-4mq4-7rw3-vm5j
Wasmer filesystem sandbox not enforced
Summary
As of Wasmer version v4.2.3, Wasm programs can access the filesystem outside of the sandbox.
Details
https://github.com/wasmerio/wasmer/issues/4267
PoC
A minimal Rust program:
fn main() {
let f = std::fs::OpenOptions::new()
.write(true)
.create_new(true)
.open("abc")
.unwrap();
}
This should be compiled with cargo build --target wasm32-wasi. The compiled program, when run with wasmer WITHOUT --dir, can still create a file in the working directory.
Impact
Service providers running untrusted Wasm code on Wasmer can unexpectedly expose the host filesystem.
- Record
GHSA-4mq4-7rw3-vm5j- CVSS 3.1
- 8.4 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-284
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
wasmer-clicrates.io |
3.0.0 up to 4.2.4 | 4.2.4 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-51661 is a high vulnerability (CVSS 8.4) in Wasmer, published December 13, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.60%, the 48th percentile. Fixed in wasmer-cli 4.2.4.
References
github.com/wasmerio/wasmer/security/advisories/GHSA-4mq4-7rw3-vm5j
nvd.nist.gov/vuln/detail/CVE-2023-51661