CVE-2026-57019
Junos OS: MX Series: Specific traffic causes an FPC to reset
Description
An Improper Validation of Specified Quantity in Input 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). When a specific packet is received from device in the same broadcast domain, an affected system calculates the packet size incorrectly. This causes further packet processing to fail, which triggers an FPC major error, resulting in a FPC reset impacting traffic until the FPC has automatically recovered. Affected scenarios are: MAP-T, or non-IP traffic encapsulated in IP (e.g. MPLS over GRE). When this issue happens the following logs can be observed: fpc<#> CMError: /fpc/0/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_LI_INT_REG_UNROLL_TAIL_LENGTH_OVF (0x2205eb), scope: pfe, category: functional, severity: major, module: MQSS(0), type: LI: Unroll TAIL length overflow, oc_category: default fpc<#> Performing action reset-fru for error /fpc/0/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_LI_INT_REG_UNROLL_TAIL_LENGTH_OVF (0x2205eb) in module: MQSS(0) with scope: pfe category: functional level: major, oc_category: default This issue affects Junos OS on MX Series: * all versions before 23.2R2-S6, * 23.4 versions before 23.4R2-S7, * 24.2 versions before 24.2R2-S4, * 24.4 versions before 24.4R2-S4, * 25.2 versions before 25.2R2.
INFO
Published Date :
July 9, 2026, 10:17 p.m.
Last Modified :
Oct. 25, 2026, 3:10 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-57019
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 8cbe9d5a-a066-4c94-8978-4b15efeae968 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 4.0 | HIGH | 8cbe9d5a-a066-4c94-8978-4b15efeae968 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Junos OS to a fixed release version.
- Apply vendor-provided patches for your MX Series.
- Review affected traffic types like MAP-T or GRE.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-57019.
| URL | Resource |
|---|---|
| https://supportportal.juniper.net/JSA110079 | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-57019 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-57019
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-57019 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-57019 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 25, 2026
Action Type Old Value New Value Added Translation Title: Junos OS de Juniper Networks, Description: Una vulnerabilidad de Validación Incorrecta de Cantidad Especificada en la Entrada en el Motor de Reenvío de Paquetes (pfe) de Juniper Networks Junos OS en la Serie MX permite a un atacante adyacente no autenticado causar una Denegación de Servicio (DoS). Cuando se recibe un paquete específico de un dispositivo en el mismo dominio de difusión, un sistema afectado calcula el tamaño del paquete incorrectamente. Esto hace que el procesamiento posterior de paquetes falle, lo que desencadena un error mayor de FPC, resultando en un reinicio de FPC que afecta el tráfico hasta que el FPC se haya recuperado automáticamente. Los escenarios afectados son: MAP-T, o tráfico no IP encapsulado en IP (por ejemplo, MPLS sobre GRE). Cuando ocurre este problema, se pueden observar los siguientes registros: fpc<#> CMError: /fpc/0/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_LI_INT_REG_UNROLL_TAIL_LENGTH_OVF (0x2205eb), alcance: pfe, categoría: funcional, gravedad: mayor, módulo: MQSS(0), tipo: LI: Desbordamiento de longitud de COLA de desenrollado, oc_categoría: predeterminada fpc<#> Realizando acción reset-fru para el error /fpc/0/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_LI_INT_REG_UNROLL_TAIL_LENGTH_OVF (0x2205eb) en el módulo: MQSS(0) con alcance: pfe categoría: funcional nivel: mayor, oc_categoría: predeterminada Este problema afecta a Junos OS en la Serie MX: * todas las versiones anteriores a 23.2R2-S6, * versiones 23.4 anteriores a 23.4R2-S7, * versiones 24.2 anteriores a 24.2R2-S4, * versiones 24.4 anteriores a 24.4R2-S4, * versiones 25.2 anteriores a 25.2R2. -
Initial Analysis by [email protected]
Jul. 13, 2026
Action Type Old Value New Value Added CPE Configuration AND OR *cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:-:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:-:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r1-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s3:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r1-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2-s3:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2-s4:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s4:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r1-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r2-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s5:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r2-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r2-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:25.2:r1-s1:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:25.2:r1-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.2:r2-s5:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:23.4:r2-s6:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.2:r2-s3:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:24.4:r2-s2:*:*:*:*:*:* *cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:* versions up to (excluding) 23.2 *cpe:2.3:o:juniper:junos:24.4:r2-s3:*:*:*:*:*:* OR cpe:2.3:h:juniper:mx240:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx480:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx960:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx2010:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx2020:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx204:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx2008:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx10008:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx10004:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx304:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx301:-:*:*:*:*:*:*:* Added Reference Type Juniper Networks, Inc.: https://supportportal.juniper.net/JSA110079 Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 10, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-57019', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-10T13:29:42.438982Z'} -
New CVE Received by [email protected]
Jul. 09, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Juniper Networks', 'product': 'Junos OS', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '23.2R2-S6', 'versionType': 'custom'}, {'status': 'affected', 'version': '23.4', 'lessThan': '23.4R2-S7', 'versionType': 'custom'}, {'status': 'affected', 'version': '24.2', 'lessThan': '24.2R2-S4', 'versionType': 'custom'}, {'status': 'affected', 'version': '24.4', 'lessThan': '24.4R2-S4', 'versionType': 'custom'}, {'status': 'affected', 'version': '25.2', 'lessThan': '25.2R2', 'versionType': 'custom'}], 'platforms': ['MX Series'], 'defaultStatus': 'unaffected'}] Added Description An Improper Validation of Specified Quantity in Input 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). When a specific packet is received from device in the same broadcast domain, an affected system calculates the packet size incorrectly. This causes further packet processing to fail, which triggers an FPC major error, resulting in a FPC reset impacting traffic until the FPC has automatically recovered. Affected scenarios are: MAP-T, or non-IP traffic encapsulated in IP (e.g. MPLS over GRE). When this issue happens the following logs can be observed: fpc<#> CMError: /fpc/0/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_LI_INT_REG_UNROLL_TAIL_LENGTH_OVF (0x2205eb), scope: pfe, category: functional, severity: major, module: MQSS(0), type: LI: Unroll TAIL length overflow, oc_category: default fpc<#> Performing action reset-fru for error /fpc/0/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_LI_INT_REG_UNROLL_TAIL_LENGTH_OVF (0x2205eb) in module: MQSS(0) with scope: pfe category: functional level: major, oc_category: default This issue affects Junos OS on MX Series: * all versions before 23.2R2-S6, * 23.4 versions before 23.4R2-S7, * 24.2 versions before 24.2R2-S4, * 24.4 versions before 24.4R2-S4, * 25.2 versions before 25.2R2. Added CVSS V4.0 AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:X/RE:M/U:X Added CVSS V3.1 AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-1284 Added Reference https://supportportal.juniper.net/JSA110079