CVE-2026-18149

Public on 2026-09-04
Modified on 2026-09-05
Description
undici's retry handler can leave an already-exposed response body pending forever. When a server returns a successful response that declares a Content-Length, sends only part of the body, and closes the connection, the retry handler retries the request. If the retry returns a non-retryable status such as 400, the handler forwards that new response downstream and replaces its internal response stream, but the original response body that the application still holds is never ended or destroyed. As a result calls that read that body never settle, and the configured body timeout does not fire because its timer is tied to the connection parser rather than the orphaned body. An attacker-controlled server can trigger this with two short responses without keeping a connection open, and repeated requests accumulate pending promises and streams that can exhaust application concurrency or memory. This affects undici versions from 7.11.0 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.
Severity
Medium severity
Medium
See what this means
CVSS v3 Base Score
5.9
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 2023 nodejs No Fix Planned
Amazon Linux 2023 nodejs20 No Fix Planned
Amazon Linux 2023 nodejs22 Not Affected
Amazon Linux 2023 nodejs24 Pending Fix
Amazon Linux 2027 Preview nodejs24 Pending Fix

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H