CVE-2026-57019
published 2026-07-09CVE-2026-57019: 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…
PriorityP433medium6.5CVSS 3.1
AVAACLPRNUINSUCNINAH
EPSS
0.27%
18.7th percentile
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.
Affected
47 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| juniper | junos | < 23.2 | 23.2 |
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CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv4.07.1HIGHCVSS:4.0/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
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VulDB
Juniper Junos OS up to 25.2R1 Packet Forwarding Engine MQSS_CMERROR_LI_INT_REG_UNROLL_TAIL_LENGTH_OVF input validation
vuldb·2026-07-10·CVSS 6.5
CVE-2026-57019 [MEDIUM] Juniper Junos OS up to 25.2R1 Packet Forwarding Engine MQSS_CMERROR_LI_INT_REG_UNROLL_TAIL_LENGTH_OVF input validation
A vulnerability has been found in Juniper Junos OS up to 23.2R2-S5/23.4R2-S6/24.2R2-S3/24.4R2-S3/25.2R1 and classified as critical. This impacts an unknown function of the file /fpc/0/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_LI_INT_REG_UNROLL_TAIL_LENGTH_OVF of the component Packet Forwarding Engine. Performing a manipulation results in improper input validation.
This vulnerability is identified as CVE-2026-57019. The attack can be initiated remotely. There is not any exploit available.
GHSA
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 caus
ghsa_unreviewed·2026-07-10
CVE-2026-57019 [HIGH] CWE-1284 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 caus
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,
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-07-09
Published