Use of Cache Containing Sensitive Information Affecting undici package, versions >=7.0.0 <7.28.0>=8.0.0 <8.5.0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-UNDICI-17372697
- published18 Jun 2026
- disclosed17 Jun 2026
- creditUnknown
Introduced: 17 Jun 2026
NewCVE-2026-9678 (opens in a new tab)How to fix?
Upgrade undici to version 7.28.0, 8.5.0 or higher.
Overview
undici is an An HTTP/1.1 client, written from scratch for Node.js
Affected versions of this package are vulnerable to Use of Cache Containing Sensitive Information in the cache interceptor. An attacker can obtain another user's authenticated response data by exploiting whitespace-padded field names in the Cache-Control header, causing the cache to incorrectly store and serve private data to subsequent callers, including unauthenticated users.
Note: This is only exploitable if the cache interceptor is explicitly enabled in shared mode, Authorization headers are forwarded upstream, and cacheable responses with non-canonical qualified private or no-cache directives are received.
Workaround
This vulnerability can be mitigated by disabling shared-cache mode for traffic that includes Authorization headers, avoiding caching responses to authenticated requests, or adding Vary: Authorization upstream.