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CVE-2022-39392 Detail

Description

Wasmtime is a standalone runtime for WebAssembly. Prior to version 2.0.2, there is a bug in Wasmtime's implementation of its pooling instance allocator when the allocator is configured to give WebAssembly instances a maximum of zero pages of memory. In this configuration, the virtual memory mapping for WebAssembly memories did not meet the compiler-required configuration requirements for safely executing WebAssembly modules. Wasmtime's default settings require virtual memory page faults to indicate that wasm reads/writes are out-of-bounds, but the pooling allocator's configuration would not create an appropriate virtual memory mapping for this meaning out of bounds reads/writes can successfully read/write memory unrelated to the wasm sandbox within range of the base address of the memory mapping created by the pooling allocator. This bug is not applicable with the default settings of the `wasmtime` crate. This bug can only be triggered by setting `InstanceLimits::memory_pages` to zero. This is expected to be a very rare configuration since this means that wasm modules cannot allocate any pages of linear memory. All wasm modules produced by all current toolchains are highly likely to use linear memory, so it's expected to be unlikely that this configuration is set to zero by any production embedding of Wasmtime. This bug has been patched and users should upgrade to Wasmtime 2.0.2. This bug can be worked around by increasing the `memory_pages` allotment when configuring the pooling allocator to a value greater than zero. If an embedding wishes to still prevent memory from actually being used then the `Store::limiter` method can be used to dynamically disallow growth of memory beyond 0 bytes large. Note that the default `memory_pages` value is greater than zero.


Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  7.4 HIGH
Vector:  CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
Base Score:  5.9 MEDIUM
Vector:  CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/bytecodealliance/wasmtime/commit/e60c3742904ccbb3e26da201c9221c38a4981d72 Patch  Third Party Advisory 
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-44mr-8vmm-wjhg Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-787 Out-of-bounds Write cwe source acceptance level NIST   Contributor acceptance level GitHub, Inc.  
CWE-125 Out-of-bounds Read Contributor acceptance level GitHub, Inc.  
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer Contributor acceptance level GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2022-39392
NVD Published Date:
11/10/2022
NVD Last Modified:
11/15/2022
Source:
GitHub, Inc.