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Vulnerability · Published Jul 20, 2022 · Assigned by GitHub_M

CVE-2022-31146Use After Free in Wasmtime

Medium 6.4

In plain English

A medium-severity use-after-free in wasmtime from bytecodealliance. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 70% of all known vulnerabilities).

Severity (CVSS 3.1)6.4Medium
Exploit odds (30 days)1.2%top 30.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Wasmtime is a standalone runtime for WebAssembly. There is a bug in the Wasmtime's code generator, Cranelift, where functions using reference types may be incorrectly missing metadata required for runtime garbage collection. This means that if a GC happens at runtime then the GC pass will mistakenly think these functions do not have live references to GC'd values, reclaiming them and deallocating them. The function will then subsequently continue to use the values assuming they had not been GC'd, leading later to a use-after-free. This bug was introduced in the migration to the `regalloc2` register allocator that occurred in the Wasmtime 0.37.0 release on 2022-05-20. This bug has been patched and users should upgrade to Wasmtime version 0.38.2. Mitigations for this issue can be achieved by disabling the reference types proposal by passing `false` to `wasmtime::Config::wasm_reference_types` or downgrading to Wasmtime 0.36.0 or prior.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Ubuntu:22.04:LTSmozjs78no fix listedUBUNTU-CVE-2022-31146
Ubuntu:22.04:LTSmozjs91no fix listedUBUNTU-CVE-2022-31146
Ubuntu:22.04:LTSthunderbirdno fix listedUBUNTU-CVE-2022-31146
Ubuntu:24.04:LTSthunderbirdno fix listedUBUNTU-CVE-2022-31146

Affected products (as reported)

VendorProductVersions
bytecodealliance wasmtime >= 0.37.0, < 0.38.2>= 0.84.0, < 0.85.2

Weakness: CWE-416 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L

References