Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Juniper | Junos | < 21.2 |
| Juniper | Lc2101 | - |
| Juniper | Lc480 | - |
| Juniper | Mx10004 | - |
| Juniper | Mx10008 | - |
Related Weaknesses (CWE)
References
- https://kb.juniper.net/JSA106011Vendor Advisory
- https://supportportal.juniper.net/JSA106011Vendor Advisory
FAQ
What is CVE-2026-21912?
CVE-2026-21912 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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 ...
How severe is CVE-2026-21912?
CVE-2026-21912 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-21912?
Check the references section above for vendor advisories and patch information. Affected products include: Juniper Junos, Juniper Lc2101, Juniper Lc480, Juniper Mx10004, Juniper Mx10008.