Is CVE-2026-53550 actively exploited?

No active exploitation of CVE-2026-53550 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-53550 be exploited remotely?

Yes. CVE-2026-53550 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-53550?

CVE-2026-53550 has a CVSS score of 5.3 (MEDIUM).

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MEDIUM

CVE-2026-53550

CWE-407Published: June 22, 2026· Updated: Jun 26, 2026

5.3

CVSS v3.1

EPSS:0.25%probability of exploitation in 30 daysPercentile:16.2th

Official Description

js-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0, a crafted YAML document can trigger algorithmic CPU exhaustion in js-yaml merge-key processing (<<) by repeating the same alias many times in a merge sequence. This causes quadratic parse-time behavior relative to input size and can block a Node.js worker/event loop for seconds with a relatively small payload (tens of KB), resulting in denial of service. The issue is in merge handling inside lib/loader.js. This vulnerability is fixed in 4.2.0.

NVD Source

Technical Analysis

CVE-2026-53550 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.