Vulnerability Monitor

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CVE-2026-21912

A Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in the method to collect FPC Ethernet firmware statistics of Juniper Networks Junos OS on MX10k Series allows a local, low-privileged attacker executing the 'show system firmware' CLI command to cause an LC480 or LC2101 line card to reset. On MX10k Series systems with LC480 or LC2101 line cards, repeated execution of the 'show system firmware' CLI command can cause the line card to crash and restart. Additionally, some time after the line card crashes, chassisd may also crash and restart, generating a core dump.This issue affects Junos OS on MX10k Series:  * all versions before 21.2R3-S10,  * from 21.4 before 21.4R3-S9,  * from 22.2 before 22.2R3-S7,  * from 22.4 before 22.4R3-S6,  * from 23.2 before 23.2R2-S2,  * from 23.4 before 23.4R2-S3,  * from 24.2 before 24.2R2.

Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 5.5, requiring local system access to exploit with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 5 products from juniper, from juniper, from juniper and 2 others, organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2026, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2026-01-15T21:16:07.357

Last Modified

2026-02-25T17:18:19.927

Status

Analyzed

Source

[email protected]

Severity

CVSSv3.1: 5.5 (MEDIUM)

Weaknesses
  • Type: Primary
    CWE-367
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System juniper junos < 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.2 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 21.4 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.2 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 22.4 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.2 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 23.4 Yes
Operating System juniper junos 24.2 Yes
Operating System juniper junos 24.2 Yes
Operating System juniper junos 24.2 Yes
Operating System juniper junos 24.2 Yes
Hardware juniper lc2101 - No
Hardware juniper lc480 - No
Hardware juniper mx10004 - No
Hardware juniper mx10008 - No
References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For juniper's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.