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Fencer Intel
high 7.5

CVE-2026-123866 json

Node.js is vulnerable to HTTP/2 response memory disclosure via a use-after-free during stream teardown

published 16h ago modified 15h ago also EUVD-2026-123687

cvss
7.5
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 use-after-free in Node.js HTTP/2 stream teardown can leak response memory, including the contents of other connections' response buffers, to a peer. When a stream is torn down while a write is still backpressured, for example by a peer RST_STREAM or by the server's own per-stream timeout destroying the stream, the stream's response buffer is freed but a reference to it is still used, so freed or unrelated heap memory is written to the socket instead of the intended response. On Node.js 26.x and 24.x the teardown can be driven purely by a remote peer once the window-size change from 26.9.0 and 24.22.0 is present, and on all supported lines the same defect is reachable through an application-initiated teardown such as a per-stream idle timeout. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

Patch / fix

  • nodejs node 22.23.5, 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-2026-123866

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-2026-123866 updated cvss 7.5

nodejs: Node.js: Information disclosure via use-after-free during HTTP/2 stream 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 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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.