Juniper Junos OS up to 24.2R1-S2 FPC header exceptional condition

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.3$0-$5k0.00

Summaryinfo

A vulnerability labeled as critical has been found in Juniper Junos OS up to 24.2R1-S2. This affects an unknown part of the component FPC. The manipulation of the argument header results in exceptional condition. This vulnerability is reported as CVE-2026-0203. The attacker must have access to the local network to execute the attack. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in Juniper Junos OS up to 24.2R1-S2. Affected is an unknown part of the component FPC. The manipulation of the argument header with an unknown input leads to a exceptional condition vulnerability. CWE is classifying the issue as CWE-755. The product does not handle or incorrectly handles an exceptional condition. This is going to have an impact on availability. CVE summarizes:

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.

The advisory is available at supportportal.juniper.net. This vulnerability is traded as CVE-2026-0203 since 10/29/2025. The exploitability is told to be easy. The attack needs to be done within the local network. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 03/11/2026).

Upgrading to version 21.2R3-S9, 21.4R3-S10, 22.2R3-S7, 22.3R3-S4, 22.4R3-S5, 23.2R2-S3, 23.4R2-S3, 24.2R1-S2 or 24.2R2 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 6.5
VulDB Meta Temp Score: 6.3

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector (juniper): 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Exceptional condition
CWE: CWE-755
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Junos OS 21.2R3-S9/21.4R3-S10/22.2R3-S7/22.3R3-S4/22.4R3-S5/23.2R2-S3/23.4R2-S3/24.2R1-S2/24.2R2

Timelineinfo

10/29/2025 CVE reserved
01/16/2026 +79 days Advisory disclosed
01/16/2026 +0 days VulDB entry created
03/11/2026 +53 days VulDB entry last update

Sourcesinfo

Vendor: juniper.net

Advisory: JSA104294
Status: Confirmed

CVE: CVE-2026-0203 (🔒)
GCVE (CVE): GCVE-0-2026-0203
GCVE (VulDB): GCVE-100-341442

Entryinfo

Created: 01/16/2026 09:10
Updated: 03/11/2026 00:59
Changes: 01/16/2026 09:10 (82), 03/11/2026 00:59 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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