Juniper Junos OS up to 23.2R2-S6/23.4R2-S6/24.2R2-S3/24.4R1 Packet Forwarding Engine memory leak

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k1.82-

Summaryinfo

A vulnerability was found in Juniper Junos OS up to 23.2R2-S6/23.4R2-S6/24.2R2-S3/24.4R1. It has been rated as critical. This affects an unknown part of the component Packet Forwarding Engine. This manipulation causes memory leak. This vulnerability is registered as CVE-2026-57027. The attack needs to be launched locally. No exploit is available.

Detailsinfo

A vulnerability classified as critical was found in Juniper Junos OS up to 23.2R2-S6/23.4R2-S6/24.2R2-S3/24.4R1. Affected by this vulnerability is an unknown function of the component Packet Forwarding Engine. The manipulation with an unknown input leads to a memory leak vulnerability. The CWE definition for the vulnerability is CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. As an impact it is known to affect availability. The summary by CVE is:

A Missing Release of Memory after Effective Lifetime vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on specific EX Series devices allows an unauthenticated adjacent attacker to cause a Denial-of-Service (DoS).When sFlow is configured in a Virtual Chassis (VC) scenario with EX4100 Series or EX4400 Series devices, multicast traffic which is received on one VC member and sent out on another member leads to a memory leak and ultimately an FPC crash and restart. The leak can be monitored by watching the continuous increase of the buffer values in the output of: user@host> show chassis fpc This issue affects Junos OS on EX4100 Series and EX4400: * all versions before 23.2R2-S7, * 23.4 versions before 23.4R2-S7, * 24.2 versions before 24.2R2-S4, * 24.4 versions before 24.4R2.

It is possible to read the advisory at supportportal.juniper.net. This vulnerability is known as CVE-2026-57027 since 06/23/2026. The exploitation appears to be easy. Attacking locally is a requirement. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 23.2R2-S7, 23.4R2-S7, 24.2R2-S4 or 24.4R2 eliminates this vulnerability.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Memory leak
CWE: CWE-401 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: Junos OS 23.2R2-S7/23.4R2-S7/24.2R2-S4/24.4R2

Timelineinfo

06/23/2026 CVE reserved
07/09/2026 +16 days VulDB entry created
07/10/2026 +0 days Advisory disclosed
07/10/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: juniper.net

Advisory: supportportal.juniper.net
Status: Confirmed

CVE: CVE-2026-57027 (🔒)
GCVE (CVE): GCVE-0-2026-57027
GCVE (VulDB): GCVE-100-377335

Entryinfo

Created: 07/10/2026 00:24
Changes: 07/10/2026 00:24 (54)
Complete: 🔍
Cache ID: 216::103

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