5.9

CVE-2026-21713: nodejs node Observable Timing Discrepancy

Analyzed
AliasesALPINE-CVE-2026-21713UBUNTU-CVE-2026-21713DEBIAN-CVE-2026-21713
Published 30-03-2026Last modified 10-05-2026

Vulnerability summary

CVE-2026-21713 is a medium (CVSS 5.9) Observable Timing Discrepancy vulnerability in nodejs node. EPSS estimates a 0.37% chance of exploitation in the next 30 days, higher than 30.5% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.9, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.9/10
010
Medium · v3.0 (CVE.org)
EPSS score
0.37%
0%100%
Low · -0.02 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 19 · Related 15
DSA-6183-1MGASA-2026-0071OPENSUSE-SU-2026:10504-1OPENSUSE-SU-2026:11110-1OPENSUSE-SU-2026:20519-1OPENSUSE-SU-2026:21058-1

Timeline

  1. 30-03-2026
    PublishedVulnerability first disclosed.
  2. 10-05-2026
    Last modifiedVulnerability information updated.

Description

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**.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.37%

Chance of exploitation in the next 30 days

Percentile

31%

Versus all other CVEs

30-day change

Decrease -0.02 pp

From 0.39% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard6 products
  • eco-nodejs-20.9.0All versions (No fix recorded)
  • nodejs-16All versions (No fix recorded)
  • nodejs-18All versions (No fix recorded)
  • nodejs-21All versions (No fix recorded)
  • nodejs-22< 22.22.3-r0
Wolfi5 products
  • nodejs-16All versions (No fix recorded)
  • nodejs-18All versions (No fix recorded)
  • nodejs-21All versions (No fix recorded)
  • nodejs-22< 22.22.3-r0
  • nodejs-23All versions (No fix recorded)
Nodejs2 products
  • node20.20.1 | 22.22.1 | 24.14.0 | 25.8.1 | ≥ 4.0, < 4.* | ≥ 5.0, < 5.* | ≥ 6.0, < 6.* | ≥ 7.0, < 7.* | ≥ 8.0, < 8.* | ≥ 9.0, < 9.* | ≥ 10.0, < 10.* | ≥ 11.0, < 11.* | ≥ 12.0, < 12.* | ≥ 13.0, < 13.* | ≥ 14.0, < 14.* | ≥ 15.0, < 15.* | ≥ 16.0, < 16.* | ≥ 17.0, < 17.* | ≥ 18.0, < 18.* | ≥ 19.0, < 19.*
  • node.js≤ 20.20.1 | ≥ 22.0.0, ≤ 22.22.1 | ≥ 24.0.0, ≤ 24.14.0 | ≥ 25.0.0, ≤ 25.8.1
Alpine1 product
  • nodejs< 22.22.2-r0 | < 24.14.1-r0
Debian1 product
  • nodejs< 18.20.4+dfsg-1~deb12u2 | < 20.19.2+dfsg-1+deb13u2 | < 22.22.2+dfsg+~cs22.19.15-1
Ubuntu1 product
  • nodejsAll versions (No fix recorded)

6 vendors · 16 products

References

8 links