Most recent entries from all

EUVD-2026-236534

fkie_cve-2022-39393

Wasmtime is a standalone runtime for WebAssembly. Prior to versions 2.0.2 and 1.0.2, there is a bug in Wasmtime's implementation of its pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance. This bug has been patched and users should upgrade to Wasmtime 2.0.2 and 1.0.2. Other mitigations include disabling the pooling allocator and disabling the `memory-init-cow`.

GHSA-wh6w-3828-g9qf — Wasmtime may have data leakage between instances in the pooling allocator

Affected: crates.io: wasmtime

### Impact

There is a bug in Wasmtime's implementation of it's pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance. The pooling instance allocator in Wasmtime works by preallocating virtual memory for a fixed number of instances to reside in and then new instantiations pick a slot to use. Most conventional modules additionally have an initial copy-on-write "heap image" which is mapped in Wasmtime into the linear memory slot. When a heap slot is deallocated Wasmtime resets all of its contents back to the initial state but it does not unmap the image in case the next instance is an instantiation of the same module.

The bug in Wasmtime occurs when a slot in the pooling allocator previously was used for a module with a heap image, meaning that its current state of memory contains the initial heap contents of that module. If the next instantiation within that slot does not itself contain a heap image then Wasmtime would leave the old heap image in place erroneously and continue with instantiation. This means that instantiations of modules without a heap image can see the initial heap image of the prior instantiation within that slot.

Heap images in Wasmtime are created by precomputing WebAssembly `data` segments into one large mapping to be placed into linear memory at a particular offset. Most modules produced by toolchains today will have a heap i…

gsd-2022-39393

RUSTSEC-2022-0075 — Bug in pooling instance allocator

Affected: crates.io: wasmtime

bug in Wasmtime's implementation of its pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance.

Mitigations are described [here](https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-wh6w-3828-g9qf).

UBUNTU-CVE-2022-39393

Affected: Ubuntu:18.04:LTS: mozjs52, Ubuntu:18.04:LTS: mozjs38, Ubuntu:20.04:LTS: mozjs68, Ubuntu:20.04:LTS: mozjs52, Ubuntu:22.04:LTS: mozjs78, Ubuntu:22.04:LTS: mozjs91, Ubuntu:22.04:LTS: thunderbird, Ubuntu:24.04:LTS: thunderbird