Junos OS FPC ICMP DoS Before 24.2R1-S2 Improper Handling
CVE-2026-0203 Published on January 15, 2026
Junos OS: Receipt of a specifically malformed ICMP packet causes an FPC restart
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 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.
Vulnerability Analysis
Weakness Type
Improper Handling of Exceptional Conditions
The software does not handle or incorrectly handles an exceptional condition.
Products Associated with CVE-2026-0203
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Affected Versions
Juniper Networks Junos OS:- Before 21.2R3-S9 is affected.
- Version 21.4 and below 21.4R3-S10 is affected.
- Version 22.2 and below 22.2R3-S7 is affected.
- Version 22.3 and below 22.3R3-S4 is affected.
- Version 22.4 and below 22.4R3-S5 is affected.
- Version 23.2 and below 23.2R2-S3 is affected.
- Version 23.4 and below 23.4R2-S3 is affected.
- Version 24.2 and below 24.2R1-S2, 24.2R2 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.