Vulnerability Details : CVE-2022-31104
Wasmtime is a standalone runtime for WebAssembly. In affected versions wasmtime's implementation of the SIMD proposal for WebAssembly on x86_64 contained two distinct bugs in the instruction lowerings implemented in Cranelift. The aarch64 implementation of the simd proposal is not affected. The bugs were presented in the `i8x16.swizzle` and `select` WebAssembly instructions. The `select` instruction is only affected when the inputs are of `v128` type. The correspondingly affected Cranelift instructions were `swizzle` and `select`. The `swizzle` instruction lowering in Cranelift erroneously overwrote the mask input register which could corrupt a constant value, for example. This means that future uses of the same constant may see a different value than the constant itself. The `select` instruction lowering in Cranelift wasn't correctly implemented for vector types that are 128-bits wide. When the condition was 0 the wrong instruction was used to move the correct input to the output of the instruction meaning that only the low 32 bits were moved and the upper 96 bits of the result were left as whatever the register previously contained (instead of the input being moved from). The `select` instruction worked correctly if the condition was nonzero, however. This bug in Wasmtime's implementation of these instructions on x86_64 represents an incorrect implementation of the specified semantics of these instructions according to the WebAssembly specification. The impact of this is benign for hosts running WebAssembly but represents possible vulnerabilities within the execution of a guest program. For example a WebAssembly program could take unintended branches or materialize incorrect values internally which runs the risk of exposing the program itself to other related vulnerabilities which can occur from miscompilations. We have released Wasmtime 0.38.1 and cranelift-codegen (and other associated cranelift crates) 0.85.1 which contain the corrected implementations of these two instructions in Cranelift. If upgrading is not an option for you at this time, you can avoid the vulnerability by disabling the Wasm simd proposal. Additionally the bug is only present on x86_64 hosts. Other aarch64 hosts are not affected. Note that s390x hosts don't yet implement the simd proposal and are not affected.
Products affected by CVE-2022-31104
- cpe:2.3:a:bytecodealliance:cranelift-codegen:*:*:*:*:*:rust:*:*
- cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*
Exploit prediction scoring system (EPSS) score for CVE-2022-31104
0.30%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 69 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2022-31104
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
6.8
|
MEDIUM | AV:N/AC:M/Au:N/C:P/I:P/A:P |
8.6
|
6.4
|
NIST | |
5.6
|
MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L |
2.2
|
3.4
|
NIST | |
4.8
|
MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L |
2.2
|
2.5
|
GitHub, Inc. |
CWE ids for CVE-2022-31104
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The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.Assigned by: security-advisories@github.com (Primary)
References for CVE-2022-31104
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https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jqwc-c49r-4w2x
Miscompilation of `i8x16.swizzle` and `select` with v128 inputs · Advisory · bytecodealliance/wasmtime · GitHubMitigation;Third Party Advisory
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https://github.com/bytecodealliance/wasmtime/pull/4317
x64: Fix codegen for the `select` instruction with v128 by alexcrichton · Pull Request #4317 · bytecodealliance/wasmtime · GitHubIssue Tracking;Patch;Third Party Advisory
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https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.wasm_simd
Config in wasmtime - RustThird Party Advisory
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https://webassembly.github.io/spec/
WebAssembly SpecificationsThird Party Advisory
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https://github.com/webassembly/simd
GitHub - WebAssembly/simd: Branch of the spec repo scoped to discussion of SIMD in WebAssemblyThird Party Advisory
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https://github.com/bytecodealliance/wasmtime/pull/4318
x64: Fix codegen for the `i8x16.swizzle` instruction by alexcrichton · Pull Request #4318 · bytecodealliance/wasmtime · GitHubIssue Tracking;Patch;Third Party Advisory
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