CVE-2026-101994: Junos OS and Junos OS Evolved: Malformed MC-LAG ICCP message causes l2ald heap disclosure or crash

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-14 · updated 2026-10-16
Weakness: CWE-130

Description

An Improper Handling of Length Parameter Inconsistency vulnerability in the l2ald daemon of Juniper Networks Junos OS and Junos OS Evolved allows an attacker who can control or impersonate a configured MC-LAG ICCP peer to disclose process heap memory or cause a denial of service via a malformed ICCP message.

Affected products

Juniper Junos OS: before 23.2R2-S7.7; from 23.4 before 23.4R2-S8.13; from 24.2 before 24.2R2-S5.5; from 24.4 before 24.4R2-S5; from 25.2 before 25.2R2-S2; from 25.4 before 25.4R1-S3 — fixed in 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3
Juniper Networks Junos OS Evolved: before 23.2R2-S7.7-EVO; from 23.4 before 23.4R2-S8.11-EVO; from 24.2 before 24.2R2-S5.6-EVO; from 24.4 before 24.4R2-S5-EVO; from 25.2 before 25.2R2-S2-EVO; from 25.4 before 25.4R1-S3-EVO — fixed in 23.2R2-S7.7-EVO, 23.4R2-S8.11-EVO, 24.2R2-S5.6-EVO, 24.4R2-S5-EVO, 25.2R2-S2-EVO, 25.2X100-D35-EVO

How to fix

Upgrade to a fixed version: Juniper Junos OS 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5; Juniper Networks Junos OS Evolved 23.2R2-S7.7-EVO, 23.4R2-S8.11-EVO, 24.2R2-S5.6-EVO, 24.4R2-S5-EVO. Check the vendor advisory for mitigations.

References

https://supportportal.juniper.net/JSA112187

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