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Medium · 5.9 CVE-2026-18149 EUVD-2026-71617GHSA-pmjh-fq2x-6v4x

undici vulnerable to Denial of Service via orphaned RetryHandler response body

Published Sep 4, 2026 · Updated Sep 4, 2026 · Assigned by openjs

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.

Affected products

VendorProductAffectedFixed
undici undici 7.11.0 – < 7.29.1, 8.0.0 – < 8.10.2 7.29.1

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 node-undici 8.10.2+dfsg+~cs3.2.2-1 —
Debian 13 node-undici No fix yet —
Debian 12 node-undici No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 node-undici No fix yet —
Ubuntu 26.04 LTS node-undici No fix yet —
Ubuntu 24.04 LTS node-undici No fix yet —
ReleasePackageFixed inAdvisory
Red Hat Hardened Images 1 grafana12.4 12.4.10-0.2.hum1 RHSA-2026:66008
Red Hat Hardened Images 1 nodejs24 +6 24.18.1-0.2.2.hum1 RHSA-2026:54438
Red Hat Hardened Images 1 nodejs24-npm 11.16.0-1.24.18.1.0.2.2.hum1 RHSA-2026:54438
Red Hat Hardened Images 1 nodejs26 +6 26.7.0-1.5.2.hum1 RHSA-2026:54389
Red Hat Hardened Images 1 nodejs26-npm 11.19.0-1.26.7.0.1.5.2.hum1 RHSA-2026:54389
Red Hat Hardened Images 1 v8-14.6-devel 14.6.202.34-1.26.7.0.1.5.2.hum1 RHSA-2026:54389

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 nodejs24 +4 1:24.21.0-1.amzn2023.0.1 ALAS2023-2026-3107
Amazon Linux 2023 nodejs24-npm 1:11.19.0-1.24.21.0.1.amzn2023.0.1 ALAS2023-2026-3107
Amazon Linux 2023 v8-13.6-devel 3:13.6.233.17-1.24.21.0.1.amzn2023.0.1 ALAS2023-2026-3107

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 nodejs 24.21.0-1 —

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling code-server 4.139.1-r2 —
Wolfi rolling lerna 10.0.1-r11 —
Wolfi rolling prism 5.16.0-r14 —

Affected packages

EcosystemPackageAffectedFixedRecord
npm undici >= 7.11.0, < 7.29.1 7.29.1 GHSA-pmjh-fq2x-6v4x
npm undici >= 8.0.0, < 8.10.2 8.10.2 GHSA-pmjh-fq2x-6v4x

Advisories 5

References