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.

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://kb.juniper.net/JSA106011
https://supportportal.juniper.net/JSA106011

Configurations

No configuration.

History

15 Jan 2026, 21:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-01-15 21:16

Updated : 2026-01-16 15:55

NVD link : CVE-2026-21912

Mitre link : CVE-2026-21912

CVE.ORG link : CVE-2026-21912

JSON object : View

Products Affected

No product.

CWE

CWE-367

Time-of-check Time-of-use (TOCTOU) Race Condition

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