CVE-2023-41880Network attack vector

Incorrect SIMD results via off-by-one shuffle immediate

Published Sep 15, 2023 · Updated Sep 24, 2024

Incorrect SIMD code generation in Bytecode Alliance Wasmtime allows attackers to alter WebAssembly computation results on x86_64 hosts. Cranelift supplies pshufd with an off-by-one shuffle immediate while lowering i64x2.shr_s with a constant shift above 32, sourcing the second lane's low half from the input's low rather than high 32 bits. Exploitation requires execution of attacker-controlled code containing that instruction on an affected x86_64 host; the error changes guest results but does not escape the WebAssembly sandbox.

CVSS severity2.2
Low
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect SIMD code generation in Bytecode Alliance Wasmtime allows attackers to alter WebAssembly computation results on x86_64 hosts. Cranelift supplies pshufd with an off-by-one shuffle immediate while lowering i64x2.shr_s with a constant shift above 32, sourcing the second lane's low half from the input's low rather than high 32 bits. Exploitation requires execution of attacker-controlled code containing that instruction on an affected x86_64 host; the error changes guest results but does not escape the WebAssembly sandbox.

The record

CVE
CVE-2023-41880
Published
Sep 15, 2023
Updated
Sep 24, 2024
Vendor
Bytecode Alliance
Product
Wasmtime
Classifications
CWE-193
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 15, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 24, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 10.0.0, < 10.0.2
  2. Affected versionversion=>= 11.0.0, < 11.0.2
  3. Affected versionversion=>= 12.0.0, < 12.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Bytecode Alliance · Wasmtimeversion=>= 10.0.0, < 10.0.2; version=>= 11.0.0, < 11.0.2; version=>= 12.0.0, < 12.0.2

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
2.2GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-193Off-by-one Error

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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