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Fencer Intel
high 8.2

CVE-2026-123863 json

Node.js is vulnerable to a remote HTTP/2 denial of service via a reachable assertion in Http2Session teardown

published 16h ago modified 15h ago also EUVD-2026-123682

cvss
8.2
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
—
no EPSS score yet
public exploits
0
none known

Summary

A reachable assertion in Node.js HTTP/2 session teardown lets any unauthenticated client abort the server, over both TLS and cleartext. A client can arrange for an Http2Stream that still holds nghttp2-allocated header buffers to outlive its session: the stream is removed from the session's stream set but never detached, so when ~Http2Session() runs the memory accounting is nonzero and the CHECK_EQ(current_nghttp2_memory_, 0) assertion fails, terminating the process. The trigger needs only a default http2 server whose handler responds before the request body has ended, which is typical. It is a variant of CVE-2024-27983 that the earlier fix did not cover, because that fix only detached streams still tracked in the session. This vulnerability affects Node.js 26.x (since 26.9.0) and 24.x (since 24.22.0).

Patch / fix

  • nodejs node 24.22.3, 26.13.1
  • nodejs Alpine 3.22, Alpine 3.21 22.23.5-r0
  • nodejs Alpine 3.24, Alpine 3.23 24.22.3-r0

alpine advisories ALPINE-CVE-2026-123863

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-123863 updated cvss 7.5

nodejs: Node.js: Denial of Service via improper HTTP/2 session teardown

  • Red Hat Hardened Images nodejs25 25.9.0-1.7.hum1, nodejs20 20.20.2-1.3.hum1, nodejs24 24.22.2-0.2.hum1, nodejs26 26.13.0-0.1.1.hum1, nodejs22 22.23.4-2.3.2.3.1.hum1
    affected: workaround, no fix available, no fix planned “Will not fix”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CVSS scores

assigned by version score vector
CNA 3.0 8.2 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Affected products

  • nodejs node

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.