GHSA-hpqh-2wqx-7qp5 · 深刻度： high · エコシステム： rust — Memory access due to code generation flaw in Cranelift module
Cranelift is an open-source code generator maintained by Bytecode Alliance. It translates a target-independent intermediate representation into executable machine code. There is a bug in 0.73 of the Cranelift x64 backend that can create a scenario that could result in a potential sandbox escape in a Wasm program. This bug was introduced in the new backend on 2020-09-08 and first included in a release on 2020-09-30, but the new backend was not the default prior to 0.73. The recently-released version 0.73 with default settings, and prior versions with an explicit build flag to select the new backend, are vulnerable. The bug in question performs a sign-extend instead of a zero-extend on a value loaded from the stack, under a specific set of circumstances. If those circumstances occur, the bug could allow access to memory addresses upto 2GiB before the start of the Wasm program heap. If the heap bound is larger than 2GiB, then it would be possible to read memory from a computable range dependent on the size of the heaps bound. The impact of this bug is highly dependent on heap implementation, specifically: * if the heap has bounds checks, and * does not rely exclusively on guard pages, and * the heap bound is 2GiB or smaller * then this bug cannot be used to reach memory from another Wasm program heap. The impact of the vulnerability is mitigated if there is no memory mapped in the range accessible using this bug, for example, if there is a 2 GiB guard region before the Wasm program heap. The bug in question performs a sign-extend instead of a zero-extend on a value loaded from the stack, when the register allocator reloads a spilled integer value narrower than 64 bits. This interacts poorly with another optimization: the instruction selector elides a 32-to-64-bit zero-extend operator when we know that an instruction producing a 32-bit value actually zeros the upper 32 bits of its destination register. Hence, we rely on these zeroed bits, but the type of the value is still i32, and the spill/reload reconstitutes those bits as the sign extension of the i32’s MSB. The issue would thus occur when: * An i32 value in a Wasm program is greater than or equal to 0x8000_0000; * The value is spilled and reloaded by the register allocator due to high register pressure in the program between the value’s definition and its use; * The value is produced by an instruction that we know to be “special” in that it zeroes the upper 32 bits of its destination: add, sub, mul, and, or; * The value is then zero-extended to 64 bits in the Wasm program; * The resulting 64-bit value is used. Under these circumstances there is a potential sandbox escape when the i32 value is a pointer. The usual code emitted for heap accesses zero-extends the Wasm heap address, adds it to a 64-bit heap base, and accesses the resulting address. If the zero-extend becomes a sign-extend, the program could reach backward and access memory up to 2GiB before the start of its heap. In addition to assessing the nature of the code generation bug in Cranelift, we have also determined that under specific circumstances, both Lucet and Wasmtime using this version of Cranelift may be exploitable. See referenced GitHub Advisory for more details.
総合評価: CVE-2021-32629 は公開エクスプロイトあり（56.8/100）。CVSS 深刻度は高。悪用される可能性が高い（EPSS 0.46%、36 パーセンタイル） 根拠: 公開エクスプロイトが 1 件参照されています（Exploit-DB）。 推奨対応: 公開エクスプロイトが確認されています。影響範囲の確認、緩和策の適用、パッチ適用を優先してください。
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。
| EDB-ID | ソース | 種別 | 公開 | リンク |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
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 | 0.06% | 0.46% | +0.40% |
| 2 | 2025-03-30 | 0.15% | 0.06% | -0.09% |
| 3 | 2025-03-29 | — | 0.15% | — |
EPSS の全履歴 （全 8 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 |
|---|---|---|---|---|---|---|
| 7.2 | 3.1 | HIGH |
|
0.8 | 5.8 | [email protected] |
| 8.8 | 3.1 | HIGH |
|
2.0 | 6.0 | [email protected] |
| 4.6 | 2.0 | MEDIUM |
|
3.9 | 6.4 | [email protected] |
GHSA-hpqh-2wqx-7qp5 · 深刻度： high · エコシステム： rust — Memory access due to code generation flaw in Cranelift module
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| bytecodealliance | cranelift-codegen | < 0.73.1 | cpe:2.3:a:bytecodealliance:cranelift-codegen:*:*:*:*:*:rust:*:* |
| URL | タグ |
|---|---|
| https://crates.io/crates/cranelift-codegen | Product Third Party Advisory |
| https://github.com/bytecodealliance/wasmtime/commit/95559c01aaa7c061088a433040f31e8291fb09d0 | Patch Third Party Advisory |
| https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hpqh-2wqx-7qp5 | Exploit Third Party Advisory |
| https://www.fastly.com/security-advisories/memory-access-due-to-code-generation-flaw-in-cranelift-module | Third Party Advisory |