CVE-2026-34971
Wasmtime Cranelift miscompile enables sandbox escape on aarch64.
Is CVE-2026-34971 being exploited?
Not confirmed. CVE-2026-34971 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.32% probability of exploitation in the next 30 days.
How severe is CVE-2026-34971?
CVE-2026-34971 is rated Critical with a CVSS score of 9.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-34971?
Yes. A fix has been recorded for CVE-2026-34971. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-34971 affect?
CVE-2026-34971 affects Wasmtime 32.0.0–36.0.6, Wasmtime 42.0.0–42.0.1, Wasmtime 43.0.0. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-34971?
Upgrade to fixed versions: 36.0.7+, 42.0.2, or 43.0.1
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Guest WebAssembly can read/write host memory, bypassing sandbox restrictions.
Patch when possible
- affected>= 32.0.0 and < 36.0.7
- affected>= 37.0.0 and < 42.0.2
- affected>= 43.0.0 and < 44.0.1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.