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CVE-2025-30647: Junos OS: MX Series: Subscriber login/logout activity will lead to a memory leak

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-04-09 · updated 2026-06-17
• Weakness: CWE-401

Description

A Missing Release of Memory after Effective Lifetime vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on MX Series allows an unauthenticated adjacent attacker to cause a Denial-of-Service (DoS). In a subscriber management scenario, login/logout activity triggers a memory leak, and the leaked memory gradually increments and eventually results in a crash.                 user@host> show chassis fpc                                        Temp    CPU Utilization (%)   CPU Utilization (%)   Memory     Utilization (%)                       Slot State       (C)     Total   Interrupt     1min   5min  15min    DRAM (MB)  Heap   Buffer                       2 Online         36       10         0          9     8     9        32768      26         0                                                                                                       This issue affects Junos OS on MX Series: * All versions before 21.2R3-S9 * from 21.4 before 21.4R3-S10 * from 22.2 before 22.2R3-S6 * from 22.4 before 22.4R3-S5 * from 23.2 before 23.2R2-S3 * from 23.4 before 23.4R2-S3 * from 24.2 before 24.2R2.

Affected products

• Juniper Junos OS: before 21.2; 21.2, 21.2-r1, 21.2-r1-s1, 21.2-r1-s2, 21.2-r2, 21.2-r2-s1 (+70) — fixed in 21.2

How to fix

Upgrade to a fixed version: Juniper Junos OS 21.2. Check the vendor advisory for mitigations.

References

• https://supportportal.juniper.net/JSA96457

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