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Fencer Vulns
medium 5.9

CVE-2026-21637 json

A flaw in Node.js TLS error handling allows remote attackers to crash or exhaust resources of a TLS server when `pskCallback` or `ALPNCallb…

published 2026-01-20 9 mo ago modified 2026-09-08 2 mo ago also BIT-node-2026-21637 , BIT-node-min-2026-21637 , EUVD-2026-3327

cvss
5.9
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits
0
none known

Summary

A flaw in Node.js TLS error handling allows remote attackers to crash or exhaust resources of a TLS server when `pskCallback` or `ALPNCallback` are in use. Synchronous exceptions thrown during these callbacks bypass standard TLS error handling paths (tlsClientError and error), causing either immediate process termination or silent file descriptor leaks that eventually lead to denial of service. Because these callbacks process attacker-controlled input during the TLS handshake, a remote client can repeatedly trigger the issue. This vulnerability affects TLS servers using PSK or ALPN callbacks across Node.js versions where these callbacks throw without being safely wrapped.

Patch / fix

  • bitnami node 20.20.0, 22.22.0, 24.13.0, 25.3.0
  • bitnami node-min 20.20.0, 22.22.0, 24.13.0, 25.3.0
  • nodejs node.js 20.20.0, 22.22.0, 24.13.0, 25.3.0
  • nodejs Debian 12 18.20.4+dfsg-1~deb12u2
  • nodejs Debian 13 20.19.2+dfsg-1+deb13u2
  • nodejs Debian 14 22.22.2+dfsg+~cs22.19.15-1

debian advisories DEBIAN-CVE-2026-21637

  • nodejs20 hummingbird 1 20.20.0-7.1.hum1
  • nodejs20-bin hummingbird 1 20.20.0-7.1.hum1
  • nodejs20-npm hummingbird 1 10.8.2-1.20.20.0.7.1.hum1
  • nodejs20-libs hummingbird 1 20.20.0-7.1.hum1
  • nodejs20-npm-bin hummingbird 1 20.20.0-7.1.hum1
  • nodejs20-full-i18n hummingbird 1 20.20.0-7.1.hum1
  • nodejs22 hummingbird 1 22.22.0-1.3.hum1
  • nodejs22-bin hummingbird 1 22.22.0-1.3.hum1

red hat advisories RHSA-2026:7386RHSA-2026:7387RHSA-2026:6431RHSA-2026:6402RHSA-2026:7675RHSA-2026:7670

  • nodejs16 SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 16.20.2-150400.3.42.1
  • nodejs18 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 18.20.8-150400.9.39.1
  • nodejs22 SLES for SAP applications 16.0, SLES 16.0 22.23.0-160000.1.1
  • nodejs22 SLE Module for Web and Scripting 15 SP7 22.22.2-150700.3.9.1
  • nodejs20 SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 20.20.2-150500.11.27.1
  • nodejs24 SLE Module for Web and Scripting 15 SP7 24.14.1-150700.15.8.1
  • nodejs24 SLES for SAP applications 16.0, SLES 16.0 24.14.1-160000.1.1
  • nodejs22 SLES for SAP applications 16.0, SLES 16.0 22.22.0-160000.1.1

suse advisories SUSE-SU-2026:4355-1SUSE-SU-2026:4261-1SUSE-SU-2026:4248-1SUSE-SU-2026:22368-1SUSE-SU-2026:1509-1SUSE-SU-2026:1478-1

  • nodejs22 openSUSE Leap 16.0 22.23.0-160000.1.1
  • nodejs26 openSUSE Tumbleweed 26.3.1-1.1
  • nodejs24 openSUSE Leap 16.0 24.14.1-160000.1.1
  • nodejs22 openSUSE Leap 16.0 22.22.0-160000.1.1
  • nodejs22 openSUSE Tumbleweed 22.22.0-1.1
  • nodejs24 openSUSE Tumbleweed 24.13.0-1.1

opensuse advisories openSUSE-SU-2026:21058-1openSUSE-SU-2026:11110-1openSUSE-SU-2026:20519-1openSUSE-SU-2026:20236-1openSUSE-SU-2026:10074-1openSUSE-SU-2026:10062-1

  • npm AlmaLinux 8 1:11.11.0-1.24.14.1.2.module_el8.10.0+4160+4819ac42
  • nodejs AlmaLinux 8 1:24.14.1-2.module_el8.10.0+4160+4819ac42
  • nodejs-libs AlmaLinux 8 1:24.14.1-2.module_el8.10.0+4160+4819ac42
  • nodejs-nodemon AlmaLinux 8 3.0.3-1.module_el8.10.0+4061+f8ceeab9
  • nodejs-full-i18n AlmaLinux 8 1:24.14.1-2.module_el8.10.0+4160+4819ac42
  • nodejs-packaging AlmaLinux 8 2021.06-6.module_el8.10.0+4086+70facd4a
  • nodejs-packaging-bundler AlmaLinux 8 2021.06-6.module_el8.10.0+4086+70facd4a
  • nodejs24-npm AlmaLinux 10 1:11.11.0-1.24.14.1.2.el10_1

almalinux advisories ALSA-2026:7670ALSA-2026:7675ALSA-2026:7350ALSA-2026:2781ALSA-2026:2782ALSA-2026:2783

  • nodejs24 Rocky Linux 10 1:24.14.1-2.el10_1
  • nodejs-nodemon Rocky Linux 8 3.0.3-1.module+el8.10.0+2084+ab509703
  • nodejs-packaging Rocky Linux 8 2021.06-6.module+el8.10.0+40048+6d99f608
  • nodejs-nodemon Rocky Linux 9 3.0.3-3.module+el9.7.0+40025+0e0cf6b2
  • nodejs-packaging Rocky Linux 9 2021.06-6.module+el9.7.0+40052+e32ea525
  • nodejs-nodemon Rocky Linux 9 3.0.1-1.module+el9.7.0+40017+f0db1785
  • nodejs-nodemon Rocky Linux 9 3.0.1-1.module+el9.7.0+40022+9ecc286c
  • nodejs-nodemon Rocky Linux 9 3.0.1-1.module+el9.7.0+40018+a011993d

rocky linux advisories RLSA-2026:7675RLSA-2026:7670RLSA-2026:7350RLSA-2026:2781RLSA-2026:2782RLSA-2026:2783

  • nodejs Alpine 3.22, Alpine 3.21 22.22.2-r0
  • nodejs Alpine 3.22 22.22.0-r0
  • nodejs Alpine 3.24, Alpine 3.23 24.14.1-r0

alpine advisories ALPINE-CVE-2026-21637

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • nodejs Azure Linux 3.0 20.14.0-13

azure linux advisories AZL-75080

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-21637 updated cvss 5.9

nodejs: Nodejs denial of service

  • Red Hat Enterprise Linux AppStream (v. 8) nodejs 20.20.0-1.module+el8.10.0+23905+c49b2aec, nodejs 22.22.0-1.module+el8.10.0+23904+2c92f862, nodejs 24.13.0-0.module+el8.10.0+23888+24fa7806, nodejs 24.14.1-2.module+el8.10.0+24190+49a46c75, nodejs-libs 22.22.0-1.module+el8.10.0+23904+2c92f862, nodejs-libs 24.13.0-0.module+el8.10.0+23888+24fa7806, +21 more
    fixed: vendor fix RHSA-2026:2422
  • Red Hat Enterprise Linux AppStream (v. 9) nodejs 20.20.0-1.module+el9.7.0+23895+0637d423, nodejs 22.22.0-1.module+el9.7.0+23896+b5802de9, nodejs 24.13.0-1.module+el9.7.0+23894+c8377628, nodejs 24.14.1-2.module+el9.7.0+24166+51c9666b, nodejs-libs 22.22.0-1.module+el9.7.0+23896+b5802de9, nodejs-libs 24.13.0-1.module+el9.7.0+23894+c8377628, +21 more
    fixed: vendor fix RHSA-2026:2783
  • Red Hat Enterprise Linux AppStream (v. 10) nodejs 22.22.0-3.el10_1, nodejs22 22.22.0-3.el10_1, nodejs24 24.13.0-1.el10_1, nodejs24 24.14.1-2.el10_1, nodejs-libs 22.22.0-3.el10_1, nodejs24-libs 24.13.0-1.el10_1, +7 more
    fixed: vendor fix RHSA-2026:1843
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) nodejs 22.22.0-1.el10_0, nodejs22 22.22.0-1.el10_0, nodejs-libs 22.22.0-1.el10_0, nodejs-full-i18n 22.22.0-1.el10_0, nodejs-npm 10.9.4-1.22.22.0.1.el10_0
    fixed: vendor fix RHSA-2026:2899
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) nodejs 20.20.0-1.module+el9.4.0+23992+5dc31998, npm 10.8.2-1.20.20.0.1.module+el9.4.0+23992+5dc31998, nodejs-nodemon 3.0.1-1.module+el9.3.0.z+20478+84a9f781, nodejs-full-i18n 20.20.0-1.module+el9.4.0+23992+5dc31998, nodejs-packaging 2021.06-4.module+el9.3.0+19518+63aad52d, nodejs-packaging-bundler 2021.06-4.module+el9.3.0+19518+63aad52d
    fixed: vendor fix RHSA-2026:2768
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) nodejs 20.20.0-1.module+el9.6.0+23988+6b9eae47, nodejs 22.22.0-1.module+el9.6.0+23985+21730e4b, nodejs-libs 22.22.0-1.module+el9.6.0+23985+21730e4b, nodejs-nodemon 3.0.1-1.module+el9.6.0+23146+be9976bd, nodejs-nodemon 3.0.1-1.module+el9.6.0+23473+45664c2d, npm 10.8.2-1.20.20.0.1.module+el9.6.0+23988+6b9eae47, +7 more
    fixed: vendor fix RHSA-2026:2767
  • Red Hat Hardened Images nodejs25 25.9.0-1.hum1, nodejs24 24.14.1-4.hum1, nodejs20 20.20.0-7.1.hum1, nodejs22 22.22.0-1.3.hum1, nodejs25-bin 25.9.0-1.hum1, nodejs24-bin 24.14.1-4.hum1, +18 more
    fixed: vendor fix RHSA-2026:7386
  • Red Hat Hardened Images v8-14.1-devel 14.1.146.11-1.25.9.0.1.hum1, v8-13.6-devel 13.6.233.17-1.24.14.1.4.hum1, v8-11.3-devel 11.3.244.8-1.20.20.0.7.1.hum1, v8-12.4-devel 12.4.254.21-1.22.22.0.1.3.hum1
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
9 mo ago

Exploit prediction

1.12% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.0 5.9 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami node
<20.20.0
>=21.0.0, <22.22.0
>=23.0.0, <24.13.0
>=25.0.0, <25.3.0
20.20.0
22.22.0
24.13.0
25.3.0
bitnami node-min
<20.20.0
>=21.0.0, <22.22.0
>=23.0.0, <24.13.0
>=25.0.0, <25.3.0
20.20.0
22.22.0
24.13.0
25.3.0

Affected products

  • nodejs node

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.