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HIGH

CVE-2026-109869

undici vulnerable to Denial of Service via unhandled error on excessive content-encodings

CVSS v3

7.5

HIGH

EPSS Score

0.3 %

exploit probability, as of 2026-10-16

CISA KEV

No

known exploited

Exploitation

none

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-109869 Red Hat Product Security115 known affected

    undici: undici: Denial of Service via unhandled stream error on excessive content encodings

    cryostat/cryostat-openshift-console-plugin-rhel9 as a component of Cryostat 4 · exploit-intelligence/vulnerability-analysis-rhel9 as a component of Exploit Intelligence · amq-broker-bin.zip as a component of Red Hat AMQ Broker 7

Full record on NVD

Description

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-10-15
Last Modified
2026-10-15

Frequently asked questions

What is CVE-2026-109869?

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.

Is CVE-2026-109869 actively exploited?

Active exploitation of CVE-2026-109869 has not been confirmed. Its EPSS score was 0.3% on 2026-10-16, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-109869?

CVE-2026-109869 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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