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Fencer Vulns
low 2.2

CVE-2023-41880 json

Miscompilation of wasm `i64x2.shr_s` instruction with constant input on x86_64

published 2023-09-05 3 y ago modified 2026-10-12 27 d ago also GHSA-gw5p-q8mj-p7gh , RUSTSEC-2023-0091 , EUVD-2023-2511

cvss
2.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits
0
none known

Summary

Wasmtime is a standalone runtime for WebAssembly. Wasmtime versions from 10.0.0 to versions 10.02, 11.0.2, and 12.0.1 contain a miscompilation of the WebAssembly `i64x2.shr_s` instruction on x86_64 platforms when the shift amount is a constant value that is larger than 32. Only x86_64 is affected so all other targets are not affected by this. The miscompilation results in the instruction producing an incorrect result, namely the low 32-bits of the second lane of the vector are derived from the low 32-bits of the second lane of the input vector instead of the high 32-bits. The primary impact of this issue is that any WebAssembly program using the `i64x2.shr_s` with a constant shift amount larger than 32 may produce an incorrect result.

This issue is not an escape from the WebAssembly sandbox. Execution of WebAssembly guest programs will still behave correctly with respect to memory sandboxing and isolation from the host. Wasmtime considers non-spec-compliant behavior as a security issue nonetheless.

This issue was discovered through fuzzing of Wasmtime's code generator Cranelift.

Wasmtime versions 10.0.2, 11.0.2, and 12.0.2 are all patched to no longer have this miscompilation. This issue only affects x86_64 hosts and the only workaround is to either scan for this pattern in wasm modules which is nontrivial or to disable the SIMD proposal for WebAssembly. Users prior to 10.0.0 are unaffected by this vulnerability.

Patch / fix

  • crates.io wasmtime 10.0.2, 11.0.2, 12.0.2
  • bytecodealliance wasmtime 10.0.2, 11.0.2, 12.0.2
  • rust-wasmtime Debian 14, Debian 13 15.0.0+dfsg-1

debian advisories DEBIAN-CVE-2023-41880

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.67% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 2.2 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 2.2 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N
OSV 3.1 2.2 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
crates.io wasmtime
>=10.0.0, <10.0.2
>=11.0.0, <11.0.2
>=12.0.0, <12.0.2
>=0.0.0-0, <10.0.2
10.0.2
11.0.2
12.0.2

Affected products

  • bytecodealliance wasmtime

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.