CVE-2026-109829
9.1, criticalundici is an HTTP client library for Node.js
- CVSS
- 9.1, critical critical CVSS v3.1
- EPSS, next 30 days
- 0.1% higher than 3.5% of scored CVEs
- Exploitation
- No public evidence
- Published
- 15 Oct 20265 days ago
Description
undici is an HTTP client library for Node.js. In versions 7.0.0 through 7.30.0 and 8.0.0 through 8.12.1, when an originless Agent composes the redirect and cache interceptors in that order with a shared cache store, the cache builds its key from the original request URL before the redirect handler changes the origin, so a response produced after a cross-origin redirect is stored under the original key. An attacker who controls the target of a redirect from a trusted URL can have their response cached under that trusted URL and served to later callers, allowing persistent cache poisoning, and the same key confusion lets a private, non-stored redirect response to a user-specific resource be stored under the original URL and served to a later unauthenticated caller, disclosing private data. Applications are affected only when an originless Agent, a shared cache store, and the redirect-then-cache composition are all used. The issue is fixed in undici 7.30.1 and 8.12.2, which verify the producing origin still matches the cache key and preserve each redirect hop's cache-control policy before storing, and users should upgrade to one of those versions or later. As a workaround, compose the cache interceptor before the redirect interceptor, use per-origin dispatchers and cache stores, or disable shared caching on redirect-capable requests.
Details
- Vendor
- Undici
- Product
- undici
- Weakness
- CWE-346 (opens in a new tab)
- Status
- Analyzed
- Updated
- 19 Oct 2026
- Assigner
- ce714d77-add3-4f53-aff5-83d477b104bb
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
References 2
The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.
Other Undici CVEs
Every Undici CVE we holdSame vendor in what we hold, not a known link between the flaws.
- CVE-2026-109383 undici is an HTTP client library for Node.js EPSS 0.2% 9.1, critical
- CVE-2026-109841 undici is an HTTP client library for Node.js EPSS 0.3% 7.5, high
- CVE-2026-109924 undici Allocation of Resources Without Limits or Throttling Vulnerability EPSS 0.3% 7.5, high
- CVE-2026-109932 undici Uncontrolled Resource Consumption Vulnerability EPSS 0.3% 7.5, high
- CVE-2026-87029 undici is an HTTP client library for Node.js EPSS 0.3% 7.5, high
- CVE-2026-84961 undici's BalancedPool constructor passes its entire options object through an internal deep-clone that serializes and reparses the value… EPSS 0.1% 9.1, critical
- CVE-2026-84933 undici Exposure of Sensitive Information Vulnerability EPSS 0.3% 8.2, high
- CVE-2026-85014 undici's experimental WebSocketStream client crashes the whole Node.js process when a remote peer closes the TCP connection without a… EPSS 0.4% 7.5, high
Beyond this page
Is CVE-2026-109829 in your network?
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Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 20 Oct 2026, not the live upstream state.