CVSS2
Attack Vector
LOCAL
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:L/AC:M/Au:N/C:N/I:P/A:P
CVSS3
Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H
EPSS
Percentile
14.2%
Wasmtime is an open source runtime for WebAssembly & WASI. In Wasmtime from version 0.19.0 and before version 0.30.0 there was a use-after-free bug when passing externref
s from the host to guest Wasm content. To trigger the bug, you have to explicitly pass multiple externref
s from the host to a Wasm instance at the same time, either by passing multiple externref
s as arguments from host code to a Wasm function, or returning multiple externref
s to Wasm from a multi-value return function defined in the host. If you do not have host code that matches one of these shapes, then you are not impacted. If Wasmtime’s VMExternRefActivationsTable
became filled to capacity after passing the first externref
in, then passing in the second externref
could trigger a garbage collection. However the first externref
is not rooted until we pass control to Wasm, and therefore could be reclaimed by the collector if nothing else was holding a reference to it or otherwise keeping it alive. Then, when control was passed to Wasm after the garbage collection, Wasm could use the first externref
, which at this point has already been freed. We have reason to believe that the effective impact of this bug is relatively small because usage of externref
is currently quite rare. The bug has been fixed, and users should upgrade to Wasmtime 0.30.0. If you cannot upgrade Wasmtime yet, you can avoid the bug by disabling reference types support in Wasmtime by passing false
to wasmtime::Config::wasm_reference_types
.
Vendor | Product | Version | CPE |
---|---|---|---|
bytecodealliance | wasmtime | * | cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:* |
fedoraproject | fedora | 34 | cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* |
fedoraproject | fedora | 35 | cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* |
crates.io/crates/wasmtime
github.com/bytecodealliance/wasmtime/commit/101998733b74624cbd348a2366d05760b40181f3
github.com/bytecodealliance/wasmtime/security/advisories/GHSA-v4cp-h94r-m7xf
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WAVBRYDDUIY2ZR3K3FO4BVYJKIMJ5TP7/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z2Z33FTXFQ6EOINVEQIP4DFBG53G5XIY/
CVSS2
Attack Vector
LOCAL
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:L/AC:M/Au:N/C:N/I:P/A:P
CVSS3
Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H
EPSS
Percentile
14.2%