Memory Leak Vulnerability in Juniper Networks Junos OS and Junos OS Evolved
CVE-2026-21909

7.1HIGH

Key Information:

Vendor

Juniper Networks
Status
Junos Os
Junos Os Evolved
Vendor
CVE Published:
15 January 2026

Badges

👾 Exploit Exists

What is CVE-2026-21909?

A vulnerability in Juniper Networks' routing protocol daemon (rpd) within Junos OS and Junos OS Evolved allows an unauthenticated attacker positioned as an adjacent IS-IS neighbor to exploit the system by sending specific update packets. This results in a memory leak that can exhaust system resources, leading to a Denial of Service (DoS) condition, which can disrupt normal network operations. It is crucial for users to regularly monitor memory usage to mitigate the impact of this vulnerability.

Affected Version(s)

Junos OS 23.2 < 23.2R2

Junos OS 23.4 < 23.4R1-S2, 23.4R2

Junos OS 24.1 < 24.1R2

References

https://supportportal.juniper.net/JSA106008
vendor-advisory
https://kb.juniper.net/JSA106008
vendor-advisory

CVSS V4

Score:
7.1
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Adjacent Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.