What is CVE-2026-21911?

CVE-2026-21911 is a medium-severity vulnerability in Juniper Junos_os_evolved, classified under Incorrect Calculation. CVSS score: 6.5/10. Published 2026-01-15.

How severe is CVE-2026-21911?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Juniper Junos_os_evolved

CVE-2026-21911

An Incorrect Calculation vulnerability in the Layer 2 Control Protocol Daemon (l2cpd) of Juniper Networks Junos OS Evolved allows an unauthenticated network-adjacent attacker flapping the management interface to cause the learning of n…

EPSS: 0.002 (13.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Juniper Junos_os_evolved — versions 21.4, 22.2, 22.3
Juniper Networks Junos Os Evolved — versions 0, 22.2, 22.3

Weakness classification (CWE)

CWE-682 — Incorrect Calculation

References

sirt@juniper.net (vendor-advisory, Vendor Advisory)
sirt@juniper.net (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-21911?: CVE-2026-21911 is a medium-severity vulnerability in Juniper Junos_os_evolved, classified under Incorrect Calculation. CVSS score: 6.5/10. Published 2026-01-15.
How severe is CVE-2026-21911?: Medium severity. CVSS v3 base score is 6.5 out of 10.