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TI-2026-17619 Aliases CVE-2026-21919GHSA-qv89-vxpv-h7vc

Junos OS and Junos OS Evolved: A high frequency of connecting and disconnecting NETCONF…

Priority LOW 31CWE-821Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

An Incorrect Synchronization vulnerability in the management daemon (mgd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-based attacker with low privileges to cause a complete Denial-of-Service (DoS) of the management plane. When NETCONF sessions are quickly established and disconnected, a locking issue causes mgd processes to hang in an unusable state. When the maximum number of mgd processes has been reached, no new logins are possible. This leads to the inability to manage the device and requires a power-cycle to recover. This issue can be monitored by checking for mgd processes in lockf state in the output of 'show system processes extensive': user@host> show system processes extensive | match mgd <pid> root       20   0 501M 4640K lockf   1 0:01 0.00% mgd If the system still can be accessed (either via the CLI or as root, which might still be possible as last resort as this won't invoke mgd), mgd processes in this state can be killed with 'request system process terminate <PID>' from the CLI or with 'kill -9 <PID>' from the shell.  This issue affects: Junos OS: * 23.4 versions before 23.4R2-S4, * 24.2 versions before 24.2R2-S1, * 24.4 versions before 24.4R1-S3, 24.4R2; This issue does not affect Junos OS versions before 23.4R1; Junos OS Evolved: * 23.4 versions before 23.4R2-S5-EVO, * 24.2 versions before 24.2R2-S1-EVO, * 24.4 versions before 24.4R1-S3-EVO, 24.4R2-EVO. This issue does not affect Junos OS Evolved versions before 23.4R1-EVO;

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00238 14th percentileScored 2026-11-07
Fix Fixed Junos OS (Juniper Networks): 23.4R2-S4, 24.2R2-S1, 24.4R1-S3 +2Junos OS Evolved (Juniper Networks): 23.4R2-S5-EVO, 24.2R2-S1-EVO, 24.4R1-S3-EVO +2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
JuniperJunos OS23.4 to before 23.4R2-S4; 24.2 to before 24.2R2-S1; 24.4 to before 24.4R1-S3, 24.4R223.4R2-S4, 24.2R2-S1, 24.4R1-S3, 24.4R2, all version prior toPatch availableCNA
JuniperJunos OS Evolved23.4 to before 23.4R2-S5-EVO; 24.2 to before 24.2R2-S1-EVO; 24.4 to before 24.4R1-S3-EVO, 24.4R2-EVO23.4R2-S5-EVO, 24.2R2-S1-EVO, 24.4R1-S3-EVO, 24.4R2-EVO, all version prior toPatch availableCNA
  • Junos OS VendorJuniper Affected 23.4 to before 23.4R2-S4; 24.2 to before 24.2R2-S1; 24.4 to before 24.4R1-S3, 24.4R2 Fixed in 23.4R2-S4, 24.2R2-S1, 24.4R1-S3, 24.4R2, all version prior to Patch available CNA
  • Junos OS Evolved VendorJuniper Affected 23.4 to before 23.4R2-S5-EVO; 24.2 to before 24.2R2-S1-EVO; 24.4 to before 24.4R1-S3-EVO, 24.4R2-EVO Fixed in 23.4R2-S5-EVO, 24.2R2-S1-EVO, 24.4R1-S3-EVO, 24.4R2-EVO, all version prior to Patch available CNA

CPE configurations NVD · 34

CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:*23.4VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:*23.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:*23.4 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r1-s2:*:*:*:*:*:*23.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:*23.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s1:*:*:*:*:*:*23.4 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s2:*:*:*:*:*:*23.4 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:23.4:r2-s3:*:*:*:*:*:*23.4 r2-s3VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:-:*:*:*:*:*:*24.2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r1:*:*:*:*:*:*24.2 r1VulnerableJuniper
  • cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:* Versions 23.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:* Versions 23.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:* Versions 23.4 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r1-s2:*:*:*:*:*:* Versions 23.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:* Versions 23.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s1:*:*:*:*:*:* Versions 23.4 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s2:*:*:*:*:*:* Versions 23.4 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:23.4:r2-s3:*:*:*:*:*:* Versions 23.4 r2-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:-:*:*:*:*:*:* Versions 24.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r1:*:*:*:*:*:* Versions 24.2 r1 Vulnerable ·Juniper
Show 24 more CPE
CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos:24.2:r1-s1:*:*:*:*:*:*24.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r1-s2:*:*:*:*:*:*24.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.2:r2:*:*:*:*:*:*24.2 r2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:*24.4VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:*24.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:*24.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos:24.4:r2:*:*:*:*:*:*24.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:-:*:*:*:*:*:*23.4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r1:*:*:*:*:*:*23.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r1-s1:*:*:*:*:*:*23.4 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r1-s2:*:*:*:*:*:*23.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2:*:*:*:*:*:*23.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s1:*:*:*:*:*:*23.4 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s2:*:*:*:*:*:*23.4 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s3:*:*:*:*:*:*23.4 r2-s3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s4:*:*:*:*:*:*23.4 r2-s4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.2:-:*:*:*:*:*:*24.2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.2:r1:*:*:*:*:*:*24.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.2:r1-s2:*:*:*:*:*:*24.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.2:r2:*:*:*:*:*:*24.2 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.4:-:*:*:*:*:*:*24.4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.4:r1:*:*:*:*:*:*24.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.4:r1-s2:*:*:*:*:*:*24.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:24.4:r2:*:*:*:*:*:*24.4 r2VulnerableJuniper
  • cpe:2.3:o:juniper:junos:24.2:r1-s1:*:*:*:*:*:* Versions 24.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r1-s2:*:*:*:*:*:* Versions 24.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.2:r2:*:*:*:*:*:* Versions 24.2 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:* Versions 24.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:* Versions 24.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:* Versions 24.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos:24.4:r2:*:*:*:*:*:* Versions 24.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:-:*:*:*:*:*:* Versions 23.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r1:*:*:*:*:*:* Versions 23.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r1-s1:*:*:*:*:*:* Versions 23.4 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r1-s2:*:*:*:*:*:* Versions 23.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2:*:*:*:*:*:* Versions 23.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s1:*:*:*:*:*:* Versions 23.4 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s2:*:*:*:*:*:* Versions 23.4 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s3:*:*:*:*:*:* Versions 23.4 r2-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2-s4:*:*:*:*:*:* Versions 23.4 r2-s4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.2:-:*:*:*:*:*:* Versions 24.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.2:r1:*:*:*:*:*:* Versions 24.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.2:r1-s2:*:*:*:*:*:* Versions 24.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.2:r2:*:*:*:*:*:* Versions 24.2 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.4:-:*:*:*:*:*:* Versions 24.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.4:r1:*:*:*:*:*:* Versions 24.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.4:r1-s2:*:*:*:*:*:* Versions 24.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:24.4:r2:*:*:*:*:*:* Versions 24.4 r2 Vulnerable ·Juniper

Remediation

  • Fix · CNA Junos OS (Juniper Networks) Fixed in 23.4R2-S4, 24.2R2-S1, 24.4R1-S3, 24.4R2, all version prior to
  • Fix · CNA Junos OS Evolved (Juniper Networks) Fixed in 23.4R2-S5-EVO, 24.2R2-S1-EVO, 24.4R1-S3-EVO, 24.4R2-EVO, all version prior to

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-21919
  2. 2026-10-03 Alias added: GHSA-qv89-vxpv-h7vc

References

Advisory 1

  • TI-2023-18638 Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to… KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-01585 Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) services KEVCVSS 3.1CRITICAL 9.8
  • TI-2015-04610 Assertion failure in ISC BIND named via TKEY queries KEVCVSS 3.1HIGH 7.5
  • TI-2025-15550 Junos OS: An local attacker with shell access can execute arbitrary code KEVCVSS 4.0MEDIUM 6.7
  • TI-2023-18644 Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload and download arbitrary files KEVCVSS 3.1MEDIUM 5.3
  • TI-2023-18640 Junos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary files KEVCVSS 3.1MEDIUM 5.3
See all 792 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences