CVE-2026-0203An Improper Handling of Exceptional Conditions vulnerability in packet processing of Juniper Networks Junos OS allows an unauthenticated, network-adjacent attacker sending a specifically malformed IC…

An Improper Handling of Exceptional Conditions vulnerability in packet processing of Juniper Networks Junos OS allows an unauthenticated, network-adjacent attacker sending a specifically malformed ICMP packet to cause an FPC to crash and restart, resulting in a Denial of Service (DoS). When an ICMP packet is received with a specifically malformed IP header value, the FPC receiving the packet crashes and restarts. Due to the specific type of malformed packet, adjacent upstream routers would not forward the packet, limiting the attack surface to adjacent networks. This issue only affects ICMPv4. ICMPv6 is not vulnerable to this issue. This issue does not affect AFT-based line cards such as the MPC10, MPC11, LC4800, LC9600, and MX304. This issue affects Junos OS:  * all versions before 21.2R3-S9,  * from 21.4 before 21.4R3-S10,  * from 22.2 before 22.2R3-S7,  * from 22.3 before 22.3R3-S4,  * 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 24.2R1-S2, 24.2R2.

CVSS

6.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness (CWE)

CWE-755

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Not given

NVD analysis

Modified

Record last updated

Jun 17, 2026

First seen by InfoSec Signals

Oct 9, 2026

The CVE record on cve.org · NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.