5.5
/ 10
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Description
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.
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.
Basic Information
ID
CVE-2026-21912
Source
juniper
Published
Jan 15, 2026 at 20:24
Modified
Jan 15, 2026 at 20:50
Affected Product
Vendor
Juniper Networks
Product
Junos OS
Affected Versions
Juniper Networks Junos OS 0
Juniper Networks Junos OS 21.4
Juniper Networks Junos OS 22.2
Juniper Networks Junos OS 22.4
Juniper Networks Junos OS 23.2
Juniper Networks Junos OS 23.4
Juniper Networks Junos OS 24.2
Juniper Networks Junos OS 21.4
Juniper Networks Junos OS 22.2
Juniper Networks Junos OS 22.4
Juniper Networks Junos OS 23.2
Juniper Networks Junos OS 23.4
Juniper Networks Junos OS 24.2