SB2026052255 - Improper access control in Wasmtime

Description

This security bulletin contains information about 1 vulnerability.

1) Improper access control (CVE-ID: CVE-2026-47261)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to modify file contents despite configured write restrictions.

The vulnerability exists due to improper access control in Dir::open_at when handling path_open or descriptor.open-at requests with the OpenFlags::TRUNCATE flag. A remote attacker can open a file with the truncate flag but without write permissions to modify file contents despite configured write restrictions.

Only embeddings that grant directory mutation permissions while restricting file permissions to read-only are affected.

Remediation

Install update from vendor's website.

References

• https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2r75-cxrj-cmph
• https://github.com/bytecodealliance/wasmtime/security/advisories