CVE-2026-21921

mediumpriority · track · 0EPSS 0.004 · 31 %ileDEEUNLUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.37% (31st) EPSS

CVSS 6.5 · medium

Is it mine?

21 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · cert_bund · ncsc_nl

EPSS · scored 2026-10-27

A Use After Free vulnerability in the chassis daemon (chassisd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-based attacker authenticated with low privileges to cause a Denial-of-Service (DoS). When telemetry collectors are frequently subscribing and unsubscribing to sensors continuously over a long period of time, telemetry-capable processes like chassisd, rpd or mib2d will crash and restart, which - depending on the process - can cause a complete outage until the system has recovered. This issue affects: Junos OS: * all versions before 22.4R3-S8, * 23.2 versions before 23.2R2-S5, * 23.4 versions before 23.4R2; Junos OS Evolved: * all versions before 22.4R3-S8-EVO, * 23.2 versions before 23.2R2-S5-EVO, * 23.4 versions before 23.4R2-EVO.

cvss

Technical severity, 0–10. One row per scoring source.

7.1

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.9–7.1

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · sirt@juniper.net USexploitability 2.8 · impact 3.6

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · NCSC-NL NL

v4.07.1highCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:Msecondary · ENISA EU

v4.07.1highCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:X/RE:M/U:Xsecondary · sirt@juniper.net US

v4.04.9mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:X/RE:M/U:Xsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-416USCWE-416US

affected products (21)

Products and version ranges known to be affected.

Juniper JUNOS OSall versionscert_bundDEcpe:/o:juniper:junos:os
Juniper JUNOS OS Evolvedall versionscert_bundDEcpe:/o:juniper:junos:os_evolved
Juniper Networks Junos OS0 → 22.4R3-S8enisa_euvdEU
Juniper Networks Junos OS23.2 → 23.2R2-S5enisa_euvdEU
Juniper Networks Junos OS23.4 → 23.4R2enisa_euvdEU
Juniper Networks Junos OS Evolved0 → 22.4R3-S8-EVOenisa_euvdEU
Juniper Networks Junos OS Evolved23.2 → 23.2R2-S5-EVOenisa_euvdEU
Juniper Networks Junos OS Evolved23.4 → 23.4R2-EVOenisa_euvdEU
Juniper Networks Junos OS≤ vers:unknown/*ncsc_nlNL
Juniper Networks Junos OS Evolved≤ vers:unknown/*ncsc_nlNL
Juniper Networks Junos Space≤ vers:unknown/*ncsc_nlNL
Juniper Networks Paragon Automation (Pathfinder, Planner, Insights)≤ vers:unknown/*ncsc_nlNL
Juniper Networks Spac≤ vers:unknown/*ncsc_nlNL
juniper junos< 22.4nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos= 22.4nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos= 23.2nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos= 23.4nvdUScpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos os evolved< 22.4nvdUScpe:2.3:o:juniper:junos_os_evolved:*:*:*:*:*:*:*:*
juniper junos os evolved= 22.4nvdUScpe:2.3:o:juniper:junos_os_evolved:*:*:*:*:*:*:*:*
juniper junos os evolved= 23.2nvdUScpe:2.3:o:juniper:junos_os_evolved:*:*:*:*:*:*:*:*

showing 20 of 21

advisories (2)

Vendor and ecosystem advisories describing this.

NCSC-2026-0017Kwetsbaarheden verholpen in Juniper Networks JunOSNL2026-01-16csaf · ncsc_nlNL
Juniper heeft kwetsbaarheden verholpen in Junos OS (Specifiek voor SRX en MX Series apparaten).
WID-SEC-W-2026-0117Juniper Junos OS, Junos Space: Mehrere SchwachstellenDeutsch2026-01-14csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Juniper JUNOS und Juniper Junos Space ausnutzen, um falsche Informationen darzustellen, beliebigen Code mit Root-Rechten auszuführen, Daten zu manipulieren, vertrauliche Informationen offenzulegen und einen Denial-of-Service-Zustand zu verursachen.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cert_bund ncsc_nl nvd NVD CVE.org MITRE

published 2026-01-15modified 2026-06-17

references (7)

External citations — patches, advisories, analysis.

scry

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