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UK Cyber Defence
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CVE-2026-18149

undici's retry handler can leave an already-exposed response body pending forever.

MEDIUM 5.9EPSS 0.48%

Does this matter?

Lower severity and a low EPSS score (0.48%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 3.1
5.9 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
0.48% probability · 41th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-772
Affected
nodejs/undici
Source
ce714d77-add3-4f53-aff5-83d477b104bb
EPSS trend
0%3%5%26 October 2026: 0.48%26 October 202626 October 2026

EPSS 0.5% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.