# Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm \`br_table\` instruction Advisory record · `GHSA-mghf-wjfp-p5xm` - **Identifiers:** `GHSA-mghf-wjfp-p5xm` · `CVE-2026-115893` · `RUSTSEC-2026-0379` - **State:** Confirmed - **Severity:** CVSS 9.9 Critical - **Critical:** Yes: CVSS 9+ - **Weakness (CWE):** [CWE-691](https://cwe.mitre.org/data/definitions/691.html) - **Tags:** [CWE-691](https://agentprime.io/advisories/tag/cwe-691.md) - **Published:** 28 Oct 2026 - **Updated:** 28 Oct 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 28 Oct 2026, 21:14 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Critical Critical, because: - CVSS score 9.9: 9.0 or more. How we decide what’s critical: ## Affected packages - `wasmtime` (crates.io): affected `<36.0.19 || >=37.0.0, <48.0.7 || >=49.0.0, <49.0.4`; fixed in `36.0.19`, `48.0.7`, `49.0.4` ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > Wasmtime, when built with the Cranelift backend on aarch64, is affected in versions before 36.0.19, from 37.0.0 before 48.0.7, and from 49.0.0 before 49.0.4. A Wasm module containing a single br_table instruction with more than about 256k targets can be compiled into an incorrect branch target, so a malicious module can redirect execution to other code and escape the sandbox. Users should upgrade to 36.0.19, 48.0.7, or 49.0.4, depending on their release line. Written 3 Nov 2026. ## Not analysed yet We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check. ## Severity and exploitation - 9.9 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`, from CNA (GitHub_M) - **CISA KEV:** Not listed. - **EPSS:** 0.0099, the 62nd percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days. ## Timeline - 31 Oct 2026, 14:24 UTC: First seen by agentprime - 31 Oct 2026, 14:24 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-mghf-wjfp-p5xm) ## Sources - [GitHub Advisory Database: GHSA-mghf-wjfp-p5xm](https://github.com/advisories/GHSA-mghf-wjfp-p5xm) - [OSV: GHSA-mghf-wjfp-p5xm](https://osv.dev/vulnerability/GHSA-mghf-wjfp-p5xm) - - - - - - - - - - - - Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code. ## Check whether this affects you A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet. - With the agentprime MCP server (), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: - In a browser: reads your lockfile in the browser, never uploading it. - Whether it touches your code, with file and line: the Claude Code plugin, - As JSON: , or `POST https://api.agentprime.io/v1/match` with your packages () --- The web page: . Everything for agents: .