Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-54786 medium CVSS 5.0

Vulnerability in wasmtime-wasi (CVE-2026-54786)

Summary

Vulnerability in wasmtime-wasi (CVE-2026-54786). Risk of unauthorized operations or information disclosure. Exploitable via fd_renumber. Mitigation: upgrade to 44.0.3 or later.

Original description

The description as published by the source.

Wasmtime is a runtime for WebAssembly. All versions prior to 24.0.10; versions 25.0.0 through those before 36.0.11; versions 37.0.0 through those before 44.0.3; and versions 45.0.0 and 45.0.1 contain a native implementation of WASIp1 which suffers from a leak in the fd_renumber function where the file descriptor being renumbered to is not properly closed. Wasmtime's implementation erroneously only updated the table of descriptors for WASIp1 and didn't update the underlying table of descriptors used by the host. This behavior means that while fd_renumber works correctly from a guest's perspective it ends up leaking resources in the host that aren't cleaned up until the corresponding Store is destroyed. In a loop, guests can use fd_renumber to cause hosts to exhaust both resources and file descriptors. This bug only affects the native implementation of WASIp1, meaning that only runtimes which load core wasm modules and expose fd_renumber are affected. Runtimes are additionally only affected if they expose the ability to acquire a file descriptor, such as opening a file. For runtimes that deny access to files they are unaffected. This issue has been fixed in versions 24.0.10, 36.0.11, 44.0.3, and 45.0.2.

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-54786 has been found in wasmtime-wasi.
Attackers can target a specific entry point like fd_renumber over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.0/10.
What to do: upgrade wasmtime-wasi to 44.0.3 or later.
If unsure, ask your IT team or search "wasmtime-wasi CVE-2026-54786" on the vendor's site.

CVE-2026-54786 (wasmtime-wasi) — CWE-400 / CVSS v3 5.0
Attack vector: remote (network-reachable) / no user interaction
Attack surface: fd_renumber / Store
Patched: 44.0.3 — apply immediately
Workaround: There are no workarounds for this issue and hosts are recommended to update.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-400) exists in wasmtime-wasi. Attackers reach the vulnerable code path via fd_renumber.

📍 Affected scope

Check the vendor advisory for the affected versions of wasmtime-wasi. Attack surface: fd_renumber / Store.

🔥 Severity

Severity: Medium (CVSS 5.0/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 44.0.3.

🛡️ Workaround

Workaround: There are no workarounds for this issue and hosts are recommended to update.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'wasmtime-wasi' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'wasmtime-wasi' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で wasmtime-wasi を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply temporary workaround mitigate 
    There are no workarounds for this issue and hosts are recommended to update.

    パッチが適用されるまでの応急処置として、There are no workarounds for this issue and hosts are recommended to update. を実施。回避策の副作用 (機能低下) を確認した上で。

  3. 3
    Apply patch patch 
    Upgrade wasmtime-wasi to 44.0.3

    ステージング環境で 44.0.3 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  4. 4
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

rust wasmtime-wasi
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"44.0.3"}]}]
crates.io wasmtime-wasi
[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"24.0.10"},{"introduced":"25.0.0"},{"fixed":"36.0.11"},{"introduced":"37.0.0"},{"fixed":"44.0.3"},{"introduced":"45.0.0"},{"fixed":"45.0.2"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

We use cookies for analytics and ad measurement. This setting applies to all Game co., Ltd. sites. Details