CVE-2026-109869: high-severity vulnerability in undici
undici vulnerable to Denial of Service via unhandled error on excessive content-encodings
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.3%
undici is an HTTP client library for Node.js. In versions 6.23.0 through 6.29.0, 7.18.0 through 7.30.0, and 8.0.0 through 8.12.1, its fetch() implementation crashes the Node.js process when a malicious server returns a response with more than five content codings and closes the connection before sending the body. undici rejects such responses because of a content-encoding limit, but it created the internal response stream before that check and returned without attaching an error listener or aborting the request, so the early close surfaces a content-length mismatch on the orphaned stream, which Node.js treats as an unhandled error and terminates the process. A remote, unauthenticated server can trigger this with a single response, even when the application correctly catches the fetch() rejection, resulting in a denial of service. The issue is fixed in undici 6.29.1, 7.30.1, and 8.12.2, and users should upgrade to one of those versions or later. There is no workaround.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
undici · undiciRelated CVEs — undici
In the same product, most dangerous first.
CVE-2026-1526HIGHundici is vulnerable to Unbounded Memory Consumption in undici WebSocket permessage-deflate DecompressionEPSS 1.2%CVE-2026-2229HIGHundici is vulnerable to Unhandled Exception in undici WebSocket Client Due to Invalid server_max_window_bits ValidationEPSS 0.9%CVE-2026-12151HIGHundici WebSocket client vulnerable to denial of service via fragment count bypassEPSS 0.8%CVE-2026-2581MEDIUMundici is vulnerable to Unbounded Memory Consumption in in Undici's DeduplicationHandler via Response Buffering leads to DoSEPSS 0.6%CVE-2026-13697HIGHundici vulnerable to cross-user information disclosure and parse-time crash via degenerate private cache directivesEPSS 0.6%CVE-2026-1525MEDIUMundici is vulnerable to Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')EPSS 0.5%