CVE-2026-34945
CVE-2026-34945 · Wasmtime leaks host data with 64-bit tables and Winch
This page contains facts from public vulnerability sources. Check the original advisory before updating.
Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Winch compiler contains a bug where a 64-bit table, part of the memory64 proposal of WebAssembly, incorrectly translated the table.size instruction. This bug could lead to disclosing data on the host's stack to WebAssembly guests. The host's stack can possibly contain sensitive data related to other host-originating operations which is not intended to be disclosed to guests. This bug specifically arose from a mistake where the return value of table.size was statically typed as a 32-bit integer, as opposed to consulting the table's index type to see how large the returned register could be. When combined with details about Wnich's ABI, such as multi-value returns, this can be combined to read stack data from the host, within a guest. This vulnerability is fixed in 36.0.7, 42.0.2, and 43.0.1.
CVSS 2.3 · Low · EPSS 0.4% · Fix available
- Published
- Updated
Stack: system
Affected products and versions
wasmtime
- Versions
- >= 25.0.0, < 36.0.7: Affected
- >= 37.0.0, < 42.0.2: Affected
- >= 43.0.0, < 44.0.1: Affected
No fix published
rust-wasmtime Debian:13
- Versions
- 26.0.1+dfsg-10
- 26.0.1+dfsg-3
- 26.0.1+dfsg-4
- 26.0.1+dfsg-5
- 26.0.1+dfsg-6
- 26.0.1+dfsg-7
- 26.0.1+dfsg-8
- 26.0.1+dfsg-9
- 27.0.0+dfsg-2
- 27.0.0+dfsg-3
- 27.0.0+dfsg-4
- 28.0.1+dfsg-1
- 28.0.1+dfsg-2
- 28.0.1+dfsg-3
- 29.0.1+dfsg-1
- 29.0.1+dfsg-2
- 29.0.1+dfsg-3
- 29.0.1+dfsg-4
- 29.0.1+dfsg-5
- 29.0.1+dfsg-6
- 29.0.1+dfsg-7
- 29.0.1+dfsg-8
- 36.0.11+dfsg-1
- 36.0.12+dfsg-1
- 36.0.12+dfsg-2
- 36.0.12+dfsg-3
- 36.0.13+dfsg-1
- 36.0.5+dfsg-1
- 36.0.5+dfsg-2
- 36.0.5+dfsg-3
- 36.0.5+dfsg-4
- 36.0.5+dfsg-5
- 36.0.6+dfsg-1
- 36.0.6+dfsg-2
- 36.0.6+dfsg-3
- 36.0.6+dfsg-4
- 36.0.6+dfsg-5
- 36.0.6+dfsg-6
- 36.0.6+dfsg-7
- 36.0.7+dfsg-1
- 36.0.8+dfsg-1
- 36.0.9+dfsg-1
- 36.0.9+dfsg-2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
rust-wasmtime Debian:14
- Versions
- 26.0.1+dfsg-10
- 26.0.1+dfsg-3
- 26.0.1+dfsg-4
- 26.0.1+dfsg-5
- 26.0.1+dfsg-6
- 26.0.1+dfsg-7
- 26.0.1+dfsg-8
- 26.0.1+dfsg-9
- 27.0.0+dfsg-2
- 27.0.0+dfsg-3
- 27.0.0+dfsg-4
- 28.0.1+dfsg-1
- 28.0.1+dfsg-2
- 28.0.1+dfsg-3
- 29.0.1+dfsg-1
- 29.0.1+dfsg-2
- 29.0.1+dfsg-3
- 29.0.1+dfsg-4
- 29.0.1+dfsg-5
- 29.0.1+dfsg-6
- 29.0.1+dfsg-7
- 29.0.1+dfsg-8
- 36.0.5+dfsg-1
- 36.0.5+dfsg-2
- 36.0.5+dfsg-3
- 36.0.5+dfsg-4
- 36.0.5+dfsg-5
- 36.0.6+dfsg-1
- 36.0.6+dfsg-2
- 36.0.6+dfsg-3
- 36.0.6+dfsg-4
- 36.0.6+dfsg-5
- 36.0.6+dfsg-6
- 36.0.6+dfsg-7
- Affected ranges
- ECOSYSTEM: < 36.0.7+dfsg-1
Update to 36.0.7+dfsg-1
rust-wasmtime Ubuntu:24.04:LTS
- Versions
- 10.0.1+dfsg-7
- 15.0.1+dfsg-4
- 16.0.0+dfsg-2
- 16.0.0+dfsg-3
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
rust-wasmtime Ubuntu:25.10
- Versions
- 26.0.1+dfsg-3
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
rust-wasmtime Ubuntu:26.10
- Versions
- 36.0.5+dfsg-1
- 36.0.13+dfsg-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
rust-wasmtime Ubuntu:26.04:LTS
- Versions
- 26.0.1+dfsg-3
- 26.0.1+dfsg-4
- 28.0.1+dfsg-3
- 29.0.1+dfsg-5
- 36.0.5+dfsg-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published