Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| bytecodealliance | wasmtime | >= 25.0.0, < 36.0.7, >= 37.0.0, < 42.0.2, >= 43.0.0, < 44.0.1 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | rust-wasmtime | 36.0.7+dfsg-1 | — |
| Debian 13 | rust-wasmtime | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | rust-wasmtime | No fix yet | — |
| Ubuntu 26.04 LTS | rust-wasmtime | No fix yet | — |
| Ubuntu 25.10 | rust-wasmtime | No fix yet | — |
| Ubuntu 24.04 LTS | rust-wasmtime | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | tree-sitter | 0.26.8-1.1 | openSUSE-SU-2026:10598-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | wash | No fix yet | — |
| Wolfi rolling | wasmcloud | 2.0.4-r0 | — |
| Wolfi rolling | wizer | 11.0.3-r10 | — |
| Wolfi rolling | yara-x | 1.15.0-r2 | — |
| Wolfi rolling | zed | 0.228.0-r3 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| crates.io | wasmtime | >= 25.0.0, < 36.0.7 | 36.0.7 | GHSA-m9w2-8782-2946 |
| crates.io | wasmtime | >= 37.0.0, < 42.0.2 | 42.0.2 | GHSA-m9w2-8782-2946 |
| crates.io | wasmtime | >= 43.0.0, < 43.0.1 | 43.0.1 | GHSA-m9w2-8782-2946 |
| crates.io | wasmtime | >= 0.0.0-0, < 36.0.7 · >= 37.0.0, < 42.0.2 · >= 43.0.0, < 43.0.1 | 36.0.7, 42.0.2, 43.0.1 | RUSTSEC-2026-0086 |
Advisories 1
- openSUSE-SU-2026:10598-1 libtree-sitter0_26-0.26.8-1.1 on GA media SUSE / openSUSE Security Updates · Apr 22, 2026