undici vulnerable to caching and replay of unsafe HTTP method responses

中 5.3CVE-2026-85008 · GHSA-8436-99hf-9mmv · 04/09/2026 公開 · 15/09/2026 更新

要点

CVE-2026-85008 は undici (nodejs), undici に影響する深刻度「中」 (CVSS 5.3) の脆弱性です。
今後30日間に悪用される確率（EPSS）：0.12%（全脆弱性の 1.7% より高い）。
対処：7.29.1, 8.10.2 以降に更新してください。

パッケージ	影響を受けるバージョン	修正済みバージョン
undici nodejs	`≥ 7.0.0, < 7.29.1≥ 8.0.0, < 8.10.2`	`7.29.18.10.2`
undici npm	`≥ 7.0.0, < 7.29.1≥ 8.0.0, < 8.10.2`	`7.29.18.10.2`

概要

Impact

undici's interceptors.cache() documents that it caches only safe HTTP methods. However, its internal skip-list is built by subtracting the configured methods from the safe-methods set, so an unsafe method (POST, PUT, PATCH, DELETE) never lands in the skip-list and is looked up against the cache store. Combined with the storage gate (canCacheResponse) having no method check, a heuristically-cacheable response (for example a 404) with an explicit Cache-Control: max-age=... to an unsafe method is stored and replayed on a subsequent identical request. The application's state-changing request never reaches the origin, and undici serves a fabricated response from the cache instead. This occurs with the default configuration (methods: ['GET']), which the public API does not allow widening to unsafe methods, so no application misuse is required; an untrusted origin can trigger it purely through its own response headers.

Patches

Upgrade to 7.29.1 or 8.10.2. The cache interceptor no longer reads from or writes to the cache for unsafe HTTP methods, while still invalidating existing cache entries on successful unsafe requests.

Workarounds

None.

NVD の説明

undici's cache interceptor documents that only safe HTTP methods are cached, but its logic to skip caching is built by subtracting the configured methods from the set of safe methods, so an unsafe method such as POST, PUT, or DELETE is never placed in the skip list and instead falls through to the full cache-read path. The response-storage gate also lacked a method check, so a response to an unsafe request that is heuristically cacheable or carries an explicit Cache-Control directive is stored and later replayed from cache. Because response headers from a remote origin are untrusted, an origin can answer once with a cacheable status and then have the client's own subsequent state-changing requests to that path served from the stale cache entry without ever reaching the origin, an integrity failure that occurs under the interceptor's default configuration. This affects undici versions from 7.0.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2.