CVE-2025-64718 | js-yaml has prototype pollution in merge (<<)

js-yaml is a JavaScript YAML parser and dumper. In js-yaml before 4.1.1 and 3.14.2, it's possible for an attacker to modify the prototype of the result of a parsed yaml document via prototype pollution (`__proto__`). All users who parse untrusted yaml documents may be impacted. The problem is patched in js-yaml 4.1.1 and 3.14.2. Users can protect against this kind of attack on the server by using `node --disable-proto=delete` or `deno` (in Deno, pollution protection is on by default).

Published: 2025-11-13 Last update: 2026-02-02 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-64718 is rated Low Risk (24/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.03%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-64718

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-14 — 0.03% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-64718

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]

Weakness enumeration for CVE-2025-64718

GitHub Security Advisory for CVE-2025-64718

GHSA-mh29-5h37-fv8m · Severity: medium · Ecosystem: npm — js-yaml has prototype pollution in merge (<<)

OS Trackers for CVE-2025-64718

vendor priority summary link
debian not yet assigned CVE-2025-64718 not yet assigned priority: Debian including 1 source packages (node-js-yaml), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. https://security-tracker.debian.org/tracker/CVE-2025-64718
redhat medium — https://access.redhat.com/security/cve/CVE-2025-64718
suse medium CVE-2025-64718 severity moderate: SUSE including 287 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 544 product×package rows across 67 product lines (Image SLES-Azure-3P, Image SLES-Azure-Basic, … (67 product lines)): Known Not Affected 282, Known Affected 231, Fixed 29, First Fixed 2. https://www.suse.com/security/cve/CVE-2025-64718/
ubuntu medium CVE-2025-64718 medium priority: Ubuntu including 1 source packages (node-js-yaml), 7 status rows across 7 suites (bionic, focal, jammy, noble, plucky, questing, upstream): needs-triage 6, ignored 1. https://ubuntu.com/security/CVE-2025-64718

Affected software / configurations for CVE-2025-64718

Vendor Product Version Raw CPE
nodeca js-yaml < 3.14.2 cpe:2.3:a:nodeca:js-yaml:*:*:*:*:*:node.js:*:*
nodeca js-yaml >= 4.0.0, < 4.1.1 cpe:2.3:a:nodeca:js-yaml:*:*:*:*:*:node.js:*:*

References for CVE-2025-64718

cvelogic Threat Intelligence