How severe is CVE-2026-34944?

CVE-2026-34944 has a CVSS 3.x base score of 5.7, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-34944 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34944?

CVE-2026-34944 affects Bytecodealliance Wasmtime. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34944?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-34944 have an EU (EUVD) identifier?

Yes. CVE-2026-34944 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21023.

When was CVE-2026-34944 published?

CVE-2026-34944 was published on 2026-04-09 and last updated on 2026-06-17.

CVE-2026-34944

CVE-2026-34944 is a medium-severity vulnerability in Bytecodealliance Wasmtime with a CVSS 3.x base score of 5.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-248.

Key facts

Severity: Medium (CVSS 3.x base score 5.7)
CVSS v4: 4.1
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-21023
Weakness: CWE-248
Affected product: Bytecodealliance Wasmtime
Published: 2026-04-09
Last modified: 2026-06-17

Description

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, On x86-64 platforms with SSE3 disabled Wasmtime's compilation of the f64x2.splat WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can result in a uncaught segfault due to loading from unmapped guard pages. With guard pages disabled it's possible for out-of-sandbox data to be loaded, but this data is not visible to WebAssembly guests. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.

Frequently asked questions

What is CVE-2026-34944?: Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, On x86-64 platforms with SSE3 disabled Wasmtime's compilation of the f64x2.splat WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can result in a uncaught segfault due to loading from unmapped guard pages. With guard pages disabled it's possible for out-of-sandbox data to be loaded, but this data is not visible to WebAssembly guests. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.
How severe is CVE-2026-34944?: CVE-2026-34944 has a CVSS 3.x base score of 5.7, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-34944 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34944?: CVE-2026-34944 affects Bytecodealliance Wasmtime. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34944?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34944 have an EU (EUVD) identifier?: Yes. CVE-2026-34944 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21023.
When was CVE-2026-34944 published?: CVE-2026-34944 was published on 2026-04-09 and last updated on 2026-06-17.

References

https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-qqfj-4vcm-26hv

Affected products (1)

cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*

More vulnerabilities in Bytecodealliance Wasmtime

CVE-2024-51745 — Critical (CVSS 10.0): Wasmtime is a fast and secure runtime for WebAssembly. Wasmtime's filesystem sandbox implementation on Windows blocks…
CVE-2026-34987 — Critical (CVSS 9.9): Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime with its Winch…
CVE-2023-26489 — Critical (CVSS 9.9): wasmtime is a fast and secure runtime for WebAssembly. In affected versions wasmtime's code generator, Cranelift, has a…
CVE-2022-39393 — High (CVSS 8.6): Wasmtime is a standalone runtime for WebAssembly. Prior to versions 2.0.2 and 1.0.2, there is a bug in Wasmtime's…
CVE-2026-34941 — High (CVSS 8.1): Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a vulnerability…
CVE-2022-24791 — High (CVSS 8.1): Wasmtime is a standalone JIT-style runtime for WebAssembly, using Cranelift. There is a use after free vulnerability in…

All CVEs affecting Bytecodealliance Wasmtime →

Other CWE-248 vulnerabilities

CVE-2018-11466 — Critical (CVSS 9.8): A vulnerability has been identified in SINUMERIK 808D V4.7 (All versions), SINUMERIK 808D V4.8 (All versions),…
CVE-2024-42037 — Critical (CVSS 9.3): Vulnerability of uncaught exceptions in the Graphics module Impact: Successful exploitation of this vulnerability may…
CVE-2025-53620 — Critical (CVSS 9.2): @builder.io/qwik-city is the meta-framework for Qwik. When a Qwik Server Action QRL is executed it dynamically load the…
CVE-2026-46689 — High (CVSS 8.7): Kanidm is an identity management platform. Prior to version 1.9.3, a single unauthenticated GET to any /scim/v1/...…
CVE-2026-9509 — High (CVSS 8.7): An unhandled exception in Suprema BioStar 2 (Server), versions 2.9.8, 2.9.10, and 2.9.11, that allows an…
CVE-2025-9124 — High (CVSS 8.7): A denial-of-service security issue in the affected product. The security issue stems from a fault occurring when a…

Browse all CWE-248 vulnerabilities →