GHSA-ff4p-7xrq-q5r8 · 深刻度： critical · エコシステム： rust — wasmtime vulnerable to guest-controlled out-of-bounds read/write on x86_64
wasmtime is a fast and secure runtime for WebAssembly. In affected versions wasmtime's code generator, Cranelift, has a bug on x86_64 targets where address-mode computation mistakenly would calculate a 35-bit effective address instead of WebAssembly's defined 33-bit effective address. This bug means that, with default codegen settings, a wasm-controlled load/store operation could read/write addresses up to 35 bits away from the base of linear memory. Due to this bug, however, addresses up to `0xffffffff * 8 + 0x7ffffffc = 36507222004 = ~34G` bytes away from the base of linear memory are possible from guest code. This means that the virtual memory 6G away from the base of linear memory up to ~34G away can be read/written by a malicious module. A guest module can, without the knowledge of the embedder, read/write memory in this region. The memory may belong to other WebAssembly instances when using the pooling allocator, for example. Affected embedders are recommended to analyze preexisting wasm modules to see if they're affected by the incorrect codegen rules and possibly correlate that with an anomalous number of traps during historical execution to locate possibly suspicious modules. The specific bug in Cranelift's x86_64 backend is that a WebAssembly address which is left-shifted by a constant amount from 1 to 3 will get folded into x86_64's addressing modes which perform shifts. For example `(i32.load (i32.shl (local.get 0) (i32.const 3)))` loads from the WebAssembly address `$local0 << 3`. When translated to Cranelift the `$local0 << 3` computation, a 32-bit value, is zero-extended to a 64-bit value and then added to the base address of linear memory. Cranelift would generate an instruction of the form `movl (%base, %local0, 8), %dst` which calculates `%base + %local0 << 3`. The bug here, however, is that the address computation happens with 64-bit values, where the `$local0 << 3` computation was supposed to be truncated to a a 32-bit value. This means that `%local0`, which can use up to 32-bits for an address, gets 3 extra bits of address space to be accessible via this `movl` instruction. The fix in Cranelift is to remove the erroneous lowering rules in the backend which handle these zero-extended expression. The above example is then translated to `movl %local0, %temp; shl $3, %temp; movl (%base, %temp), %dst` which correctly truncates the intermediate computation of `%local0 << 3` to 32-bits inside the `%temp` register which is then added to the `%base` value. Wasmtime version 4.0.1, 5.0.1, and 6.0.1 have been released and have all been patched to no longer contain the erroneous lowering rules. While updating Wasmtime is recommended, there are a number of possible workarounds that embedders can employ to mitigate this issue if updating is not possible. Note that none of these workarounds are on-by-default and require explicit configuration: 1. The `Config::static_memory_maximum_size(0)` option can be used to force all accesses to linear memory to be explicitly bounds-checked. This will perform a bounds check separately from the address-mode computation which correctly calculates the effective address of a load/store. Note that this can have a large impact on the execution performance of WebAssembly modules. 2. The `Config::static_memory_guard_size(1 << 36)` option can be used to greatly increase the guard pages placed after linear memory. This will guarantee that memory accesses up-to-34G away are guaranteed to be semantically correct by reserving unmapped memory for the instance. Note that this reserves a very large amount of virtual memory per-instances and can greatly reduce the maximum number of concurrent instances being run. 3. If using a non-x86_64 host is possible, then that will also work around this bug. This bug does not affect Wasmtime's or Cranelift's AArch64 backend, for example.
総合評価: CVE-2023-26489 は中リスク（61.8/100）。CVSS 深刻度は重大。悪用される可能性が高い（EPSS 1.25%、65 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 | 1.94% | 1.25% | -0.68% |
| 2 | 2026-06-10 | 2.65% | 1.94% | -0.71% |
| 3 | 2026-05-25 | — | 2.65% | — |
EPSS の全履歴 （全 24 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 |
|---|---|---|---|---|---|---|
| 9.9 | 3.1 | CRITICAL |
|
3.1 | 6.0 | [email protected] |
| 9.9 | 3.1 | CRITICAL |
|
3.1 | 6.0 | [email protected] |
GHSA-ff4p-7xrq-q5r8 · 深刻度： critical · エコシステム： rust — wasmtime vulnerable to guest-controlled out-of-bounds read/write on x86_64
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
unimportant | CVE-2023-26489 unimportant priority: Debian including 1 source packages (rust-wasmtime), 3 status rows across 3 suites (forky, sid, trixie): resolved 3. | https://security-tracker.debian.org/tracker/CVE-2023-26489 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| bytecodealliance | cranelift-codegen | >= 0.84.0, < 0.91.1 | cpe:2.3:a:bytecodealliance:cranelift-codegen:*:*:*:*:*:rust:*:* |
| bytecodealliance | cranelift-codegen | 0.92.0 | cpe:2.3:a:bytecodealliance:cranelift-codegen:0.92.0:*:*:*:*:rust:*:* |
| bytecodealliance | cranelift-codegen | 0.93.0 | cpe:2.3:a:bytecodealliance:cranelift-codegen:0.93.0:*:*:*:*:rust:*:* |
| bytecodealliance | wasmtime | >= 0.37.0, < 4.0.1 | cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* |
| bytecodealliance | wasmtime | 5.0.0 | cpe:2.3:a:bytecodealliance:wasmtime:5.0.0:*:*:*:*:rust:*:* |
| bytecodealliance | wasmtime | 6.0.0 | cpe:2.3:a:bytecodealliance:wasmtime:6.0.0:*:*:*:*:rust:*:* |