GHSA-jhxm-h53p-jm7w · 深刻度： critical · エコシステム： rust — Wasmtime: Miscompiled guest heap access enables sandbox escape on aarch64 Cranelift
Wasmtime is a runtime for WebAssembly. From 32.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Cranelift compilation backend contains a bug on aarch64 when performing a certain shape of heap accesses which means that the wrong address is accessed. When combined with explicit bounds checks a guest WebAssembly module this can create a situation where there are two diverging computations for the same address: one for the address to bounds-check and one for the address to load. This difference in address being operated on means that a guest module can pass a bounds check but then load a different address. Combined together this enables an arbitrary read/write primitive for guest WebAssembly when accesssing host memory. This is a sandbox escape as guests are able to read/write arbitrary host memory. This vulnerability has a few ingredients, all of which must be met, for this situation to occur and bypass the sandbox restrictions. This miscompiled shape of load only occurs on 64-bit WebAssembly linear memories, or when Config::wasm_memory64 is enabled. 32-bit WebAssembly is not affected. Spectre mitigations or signals-based-traps must be disabled. When spectre mitigations are enabled then the offending shape of load is not generated. When signals-based-traps are disabled then spectre mitigations are also automatically disabled. The specific bug in Cranelift is a miscompile of a load of the shape load(iadd(base, ishl(index, amt))) where amt is a constant. The amt value is masked incorrectly to test if it's a certain value, and this incorrect mask means that Cranelift can pattern-match this lowering rule during instruction selection erroneously, diverging from WebAssembly's and Cranelift's semantics. This incorrect lowering would, for example, load an address much further away than intended as the correct address's computation would have wrapped around to a smaller value insetad. This vulnerability is fixed in 36.0.7, 42.0.2, and 43.0.1.
総合評価: CVE-2026-34971 は中リスク（42.3/100）。CVSS 深刻度は重大。悪用される可能性が高い（EPSS 0.26%、17 パーセンタイル） 推奨対応: 影響資産を整理し、修補計画に組み込んでください。
リスクは変動します。再評価に基づき、本ページの表示内容を更新しています。
EPSS は日次で悪用されやすさの相対度合いを推定します。パーセンタイルは採点済み CVE の中での相対位置（高いほど相対的に深刻）を示します。
| # | 日付 | 旧 EPSS スコア | 新 EPSS スコア | Δ（新 − 旧） |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.01% | 0.26% | +0.25% |
| 2 | 2026-04-10 | — | 0.01% | — |
EPSS の全履歴 （全 2 件）
この CVE の CVSS 指標。
| ベーススコア | バージョン | 深刻度 | ベクトル | 悪用しやすさ | 影響 | スコアの出典 |
|---|---|---|---|---|---|---|
| 9.0 | 4.0 | CRITICAL |
|
— | — | [email protected] |
| 7.8 | 3.1 | HIGH |
|
1.1 | 6.0 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
GHSA-jhxm-h53p-jm7w · 深刻度： critical · エコシステム： rust — Wasmtime: Miscompiled guest heap access enables sandbox escape on aarch64 Cranelift
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2026-34971 not yet assigned priority: Debian including 1 source packages (rust-wasmtime), 3 status rows across 3 suites (forky, sid, trixie): resolved 2, open 1. | https://security-tracker.debian.org/tracker/CVE-2026-34971 |
redhat
|
high | — | https://access.redhat.com/security/cve/CVE-2026-34971 |
suse
|
high | — | https://www.suse.com/security/cve/CVE-2026-34971/ |
ubuntu
|
medium | CVE-2026-34971 medium priority: Ubuntu including 1 source packages (rust-wasmtime), 4 status rows across 4 suites (jammy, noble, questing, upstream): needs-triage 3, DNE 1. | https://ubuntu.com/security/CVE-2026-34971 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| bytecodealliance | wasmtime | >= 32.0.0, < 36.0.7 | cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* |
| bytecodealliance | wasmtime | >= 37.0.0, < 42.0.2 | cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* |
| bytecodealliance | wasmtime | 43.0.0 | cpe:2.3:a:bytecodealliance:wasmtime:43.0.0:*:*:*:*:rust:*:* |
| URL | タグ |
|---|---|
| https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jhxm-h53p-jm7w | Mitigation Vendor Advisory |