# CVE-2026-115893: Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction - **Severity:** Critical 9.9 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Fix available:** Yes - **Published:** 23 Oct 2026 - **Updated:** 29 Oct 2026 - **Also known as:** AZL-111428, AZL-111434, DEBIAN-CVE-2026-115893, GHSA-mghf-wjfp-p5xm, RUSTSEC-2026-0379, UBUNTU-CVE-2026-115893 ## What is CVE-2026-115893? CVE-2026-115893 is a critical vulnerability in bytecodealliance wasmtime, published on 23 Oct 2026. ### Official description Wasmtime is a runtime for WebAssembly. Prior to 36.0.19, 48.0.7, and 49.0.4, the Cranelift compiler backend on aarch64 can compile a Wasm br_table instruction with more than approximately 256,000 targets so that it has an incorrect conditional branch target. The branch can then jump to arbitrary other code at a user-controlled offset, allowing a user-controlled Wasm module to escape the sandbox on aarch64 engines using the default Cranelift backend. This issue is fixed in versions 36.0.19, 48.0.7, and 49.0.4. Weakness: CWE-691 (Insufficient Control Flow Management) ## Which versions are affected by CVE-2026-115893? 7 open source packages ship an affected version, including wasmtime. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `wasmtime` | crates.io | All versions | 36.0.19 | | `wasmtime` | crates.io | All versions | 36.0.19 | | `wasmtime` | crates.io | From 0.0.0-0 | 36.0.19, 48.0.7, 49.0.4 | | `wasmtime` | crates.io | From 37.0.0 | 48.0.7 | | `wasmtime` | crates.io | From 37.0.0 | 48.0.7 | | `wasmtime` | crates.io | From 49.0.0 | 49.0.4 | | `wasmtime` | crates.io | From 49.0.0 | 49.0.4 | ## How do I fix CVE-2026-115893? Upgrade wasmtime to a fixed version for your release line: 36.0.19, 48.0.7 or 49.0.4. ## Is CVE-2026-115893 being exploited? There is no known exploitation of CVE-2026-115893 in the wild and no public exploit code. Public exploit code: - CVE-2026-115893: full Wasmtime aarch64 Cranelift br_table sandbox-escape public exploit, PoV, calibration notes, and verification evidence. (github_poc): https://github.com/shreyas-malhotra/CVE-2026-115893-wasmtime-sandbox-escape ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-115893 and fix it if it is affected. What it is: CVE-2026-115893 is a critical vulnerability in bytecodealliance wasmtime, published on 23 Oct 2026. Exploitation: There is no known exploitation of CVE-2026-115893 in the wild and no public exploit code. Affected packages and fixed versions: - wasmtime (crates.io): affected all versions; fixed in 36.0.19 - wasmtime (crates.io): affected all versions; fixed in 36.0.19 - wasmtime (crates.io): affected from 0.0.0-0; fixed in 36.0.19, 48.0.7, 49.0.4 - wasmtime (crates.io): affected from 37.0.0; fixed in 48.0.7 - wasmtime (crates.io): affected from 37.0.0; fixed in 48.0.7 - wasmtime (crates.io): affected from 49.0.0; fixed in 49.0.4 - wasmtime (crates.io): affected from 49.0.0; fixed in 49.0.4 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-115893/ (Markdown: https://insights.sbomify.com/CVE-2026-115893/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-115893 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-115893 - OSV: https://osv.dev/vulnerability/CVE-2026-115893 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-115893/ Summaries are generated and may contain mistakes; the official description above is the record.