Symlink bypasses filesystem sandbox in wasmer

published 2024-06-07 2 y ago modified 2026-09-10 1 mo ago also EUVD-2024-1924 , GHSA-55f3-3qvg-8pv5

cvss: 2.9; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits: 0; none known

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.

Patch / fix

fixed in 1 links 1

wasmer wasmer 4.3.2

github.com/wasmerio/wasmer@b9483d0 commit

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-06-28)

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	2.9	CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
GitHub	3.1	2.9	CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
crates.io	wasmer	<=4.3.1	no fix listed

Affected products

wasmerio wasmer
wasmer wasmer

Classification

Weakness

CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary