Riskcovery

CVE-2026-21912

Junos OS: MX10k Series: 'show system firmware' CLI command may lead to LC480 or LC2101 line card reset

State
Published
Severity
6.8 Medium
Published
Jan 15, 2026
Updated
Jan 15, 2026
Reserved
Jan 5, 2026

Read the record on cve.org

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.

Scores

CVSSScoreVectorSource
4.06.8 MediumCVSS:4.0/AV:L/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:M/U:Amberjuniper
3.15.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hjuniper

Weaknesses

  • CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition

Affected Products

ProductVersions
Junos OSJuniper Networks
  • before 21.2R3-S10Affected
  • 21.4 to before 21.4R3-S9Affected
  • 22.2 to before 22.2R3-S7Affected
  • 22.4 to before 22.4R3-S6Affected
  • 23.2 to before 23.2R2-S2Affected
  • 23.4 to before 23.4R2-S3Affected
  • 24.2 to before 24.2R2Affected

References

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