CVE-2026-115889 | Vulnerability Intelligence

Stored catalog record

Source record retrieved 2026-10-28T10:26:58.767309+00:00. Scheduled imports handle updates; this page does not assert that the provider was queried just now.

Vulnerability overview

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make Cranelift reference incorrect IR values, causing arbitrary miscompilation, type confusion, and other attacker-controlled effects that may escape the Wasm sandbox on any architecture using the default Cranelift backend. This issue is fixed in versions 36.0.19 and 43.0.0.

Patch review priority

Critical technical severity

CVSS is at least 9.0; exploitation is not established by severity alone.

FIRST EPSS: 0.45% · percentile 39.2 · score date 2026-10-27.

EPSS estimates probability of exploitation in the next 30 days. It does not measure your exposure or prove exploitation. The elevated threshold is 10%; CISA KEV takes precedence. About FIRST EPSS ↗

Severity and scoring

CVSS score: 9.9 · CRITICAL
CVSS version: 3.1
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Weaknesses: CWE-197, CWE-843

CVSS measures technical severity; it does not establish whether this vulnerability is being exploited in your environment.

Known exploitation and remediation

Not listed in the CISA catalog retrieved for this record. This does not establish that exploitation has not occurred.

Verify affected versions and patch availability in the vendor advisory before making changes.

Affected products and versions

NVD has not supplied affected-version configurations for this record. Check the vendor references below.

Advisories and references

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