What is CVE-2026-123862?
An uncatchable exception in the Node.js zlib streaming API lets a peer crash a process by disconnecting while data is being compressed. zlib.params() queues a flush and completes its work in that write's callback; if the stream is destroyed first, as pipeline() does when the peer goes away, Writable still invokes the callback with an error, but the callback ignores its arguments and asserts that the native handle still exists. The handle is gone, so an ERR_INTERNAL_ASSERTION is thrown from inside stream internals and bypasses the stream's error event, the params() callback, and the pipeline() callback, terminating the process. An application is affected only if it calls deflate.params() while streaming to a peer, which is uncommon. This vulnerability affects Node.js 26.x, 24.x, and 22.x.
The record classifies CVE-2026-123862 under weakness class CWE-248. Its CVSS v3 base vector states that the flaw requires local access to the host, needs no prior authentication, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 1 day ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 2.9 — LOW
CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 1.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-11-11
Is CVE-2026-123862 being exploited?
It currently carries a trending score of 35 in the Threadlinqs vulnerability feed.
Affected products and versions
- nodejs: node
How to fix CVE-2026-123862
Vendor advisory: https://nodejs.org/en/blog/vulnerability/november-2026-security-releases. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-123862
1 tracked threat in the Threadlinqs corpus references CVE-2026-123862, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, NVD, GitHub Security Advisories. This product uses the NVD API but is not endorsed or certified by the NVD.