CVE-2026-21713

A flaw in Node.js HMAC verification uses a non-constant-time comparison when validating user-provided signatures, potentially leaking timing information proportional to the number of matching bytes. Under certain threat models where high-resolution timing measurements are possible, this behavior could be exploited as a timing oracle to infer HMAC values. Node.js already provides timing-safe comparison primitives used elsewhere in the codebase, indicating this is an oversight rather than an intentional design decision. This vulnerability affects **20.x, 22.x, 24.x, and 25.x**.

Published: 2026-03-30 Last update: 2026-05-10 Assigner: [email protected] Source: [email protected]
NVD Status：Awaiting Analysis，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-21713 is rated Low Risk (24.1/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.01%). 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-2026-21713

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 2026-03-31 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-21713

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.0 MEDIUM
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 [email protected]

Weakness enumeration for CVE-2026-21713

GitHub Security Advisory for CVE-2026-21713

GHSA-6r7g-3mm3-fhw7 · Severity: medium — A flaw in Node.js HMAC verification uses a non-constant-time comparison when validating user...

OS Trackers for CVE-2026-21713

vendor priority summary link
alpine — CVE-2026-21713: 1 source package rows (nodejs); 4 state rows across 4 repos (3.21-main, 3.22-main, 3.23-main, edge-main); fixed 4, open 0. https://security.alpinelinux.org/vuln/CVE-2026-21713
debian unimportant CVE-2026-21713 unimportant priority: Debian including 1 source packages (nodejs), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-21713
redhat medium — https://access.redhat.com/security/cve/CVE-2026-21713
suse medium CVE-2026-21713 severity moderate: SUSE including 66 source package names (corepack24-24.14.1-1.1, corepack24-24.14.1-160000.1.1, …), 137 product×package rows across 20 product lines (SUSE Liberty Linux 8, SUSE Liberty Linux 9, … (20 product lines)): Known Not Affected 79, Fixed 53, First Fixed 5. https://www.suse.com/security/cve/CVE-2026-21713/
ubuntu medium CVE-2026-21713 medium priority: Ubuntu including 1 source packages (nodejs), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): needs-triage 7, released 1. https://ubuntu.com/security/CVE-2026-21713

Affected software / configurations for CVE-2026-21713

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-21713

cvelogic Threat Intelligence