CVE-2026-115889
CRITICALDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:H/E:U
Exploit Intelligence
Low risk: more likely to be exploited than 39% of all known CVEs.
References
Related Vulnerabilities
Other CWE-197 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-42475 | Critical | 9.8 | 99% | KEV + Ransom | Fix |
| CVE-2025-6965 | High | 7.7 | 73% | - | Fix |
| CVE-2024-21310 | High | 7.8 | 12% | - | Fix |
| CVE-2024-43639 | Critical | 9.8 | 8.9% | - | Fix |
| CVE-2024-38125 | High | 7.8 | 5.9% | - | Fix |
| CVE-2024-28944 | High | 8.8 | 2.4% | - | Fix |
Common questions
How do I fix CVE-2026-115889?
Upgrade wasmtime to 43.0.0 or later.
Is CVE-2026-115889 being actively exploited?
Not that we know of. CVE-2026-115889 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.45% is the estimated probability that it will be exploited in the next 30 days. That is higher than 39% of all scored CVEs.
How severe is CVE-2026-115889?
CVE-2026-115889 has a CVSS v3 base score of 9.9, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-115889 affect?
Published advisories record a fix for wasmtime (crates.io (Rust)). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-26.