Wasmtime is a runtime for WebAssembly. In versions prior to 24.0.9, 36.0.10, and 44.0.2, when a filesystem preopen is given DirPerms::all() and FilePerms::READ without FilePerms::WRITE, this access control mechanism can be bypassed via the wasip2 descriptor.open-at or wasip1 path_open interfaces by opening a file with only the OpenFlags::TRUNCATE oflag. The root cause is that the clause handling OpenFlags::TRUNCATE in crates/wasi/src/filesystem.rs (Dir::open_at, lines 967–969) did not set open_mode |= OpenMode::WRITE;, which is later used for the access control check against FilePerms to determine whether opening the file is permitted; the single-line fix adds that missing assignment, after which the affected calls correctly fail with error-code.not-permitted and ERRNO_PERM respectively. Only wasmtime-wasi embeddings that combine DirPerms::MUTATE with FilePerms::READ are affected by this bug. In particular, the Wasmtime project's wasmtime-cli's use of wasmtime-wasi is not affected, because it always sets FilePerms::all() for all preopens. This issue has been fixed in versions 24.0.9, 36.0.10 and44.0.2.
References
| Link | Resource |
|---|---|
| https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.9 | Release Notes |
| https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.10 | Release Notes |
| https://github.com/bytecodealliance/wasmtime/releases/tag/v44.0.2 | Release Notes |
| https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.0 | Release Notes |
| https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2r75-cxrj-cmph | Mitigation Vendor Advisory |
Configurations
Configuration 1 (hide)
|
History
17 Jun 2026, 16:42
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.9 - Release Notes | |
| References | () https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.10 - Release Notes | |
| References | () https://github.com/bytecodealliance/wasmtime/releases/tag/v44.0.2 - Release Notes | |
| References | () https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.0 - Release Notes | |
| References | () https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2r75-cxrj-cmph - Mitigation, Vendor Advisory | |
| CPE | cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* | |
| First Time |
Bytecodealliance
Bytecodealliance wasmtime |
|
| CWE | NVD-CWE-noinfo |
15 Jun 2026, 21:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-06-15 21:17
Updated : 2026-06-17 16:42
NVD link : CVE-2026-47261
Mitre link : CVE-2026-47261
CVE.ORG link : CVE-2026-47261
JSON object : View
Products Affected
bytecodealliance
- wasmtime
CWE
