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Junos Os CVE-2026-57027

| EUVDEUVD-2026-42715 HIGH
Memory Leak (CWE-401)
2026-07-09 juniper GHSA-2xj6-hwhm-5m6g
7.1
CVSS 4.0 · Vendor: juniper
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Severity by source

Vendor (juniper) PRIMARY
7.1 MEDIUM
CVSS: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
vuln.today AI
6.5 MEDIUM

Adjacent L2 multicast trigger (AV:A), no auth or interaction (PR:N/UI:N), simple to trigger (AC:L), pure availability impact from FPC crash (A:H), no confidentiality/integrity effect.

3.1 AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
4.0 AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L

Primary rating from Vendor (juniper).

CVSS VectorVendor: juniper

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
X

Lifecycle Timeline

7
Patch available
Jul 09, 2026 - 23:02 EUVD
Analysis Updated
Jul 09, 2026 - 22:29 vuln.today
v3 (cvss_changed)
Analysis Updated
Jul 09, 2026 - 22:28 vuln.today
v2 (cvss_changed)
Re-analysis Queued
Jul 09, 2026 - 22:22 vuln.today
cvss_changed
Severity Changed
Jul 09, 2026 - 22:22 NVD
MEDIUM HIGH
CVSS changed
Jul 09, 2026 - 22:22 NVD
6.5 (MEDIUM) 7.1 (HIGH)
Analysis Generated
Jul 09, 2026 - 22:21 vuln.today

DescriptionCVE.org

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.

AnalysisAI

Denial-of-service in Juniper Junos OS on EX4100 and EX4400 Series switches allows an unauthenticated adjacent attacker to exhaust packet-forwarding-engine memory and crash the Flexible PIC Concentrator (FPC). The flaw triggers only when sFlow monitoring is enabled in a Virtual Chassis and multicast traffic ingresses on one VC member and egresses on another, causing a slow buffer leak that culminates in an FPC crash and restart. There is no public exploit identified at time of analysis and it is not listed in CISA KEV, but the low attack complexity and lack of authentication make it a credible availability risk for affected deployments.

CVE-2026-57026 HIGH
8.7 Jul 09

Denial-of-service in Juniper Networks Junos OS on MX Series (with SPC3) and SRX Series devices allows an unauthenticated

CVE-2026-57023 HIGH
8.7 Jul 09

Remote denial of service in Juniper Networks Junos OS on MX Series (with SPC3) and SRX Series firewalls lets an unauthen

CVE-2025-30650 HIGH
8.4 Apr 08

Privilege escalation in Juniper Networks Junos OS allows high-privileged local attackers to gain root access on Linux-ba

CVE-2026-57022 HIGH
8.2 Jul 09

Denial-of-service in the Packet Forwarding Engine (PFE) of Juniper Junos OS on MX (with SPC3) and SRX-series firewalls l

CVE-2026-57030 HIGH
8.2 Jul 09

Denial-of-service in Juniper Networks Junos OS on SRX Series devices lets an unauthenticated, network-based attacker exh

CVE-2026-57032 HIGH
7.1 Jul 09

Denial-of-service in Juniper Networks Junos OS on EX Series switches (EX2300, EX3400, EX4000, EX4100, EX4400) lets a low

CVE-2026-57020 HIGH
7.1 Jul 09

Denial-of-service in Juniper Networks Junos OS on QFX10000 Series switches allows an unauthenticated, adjacent (Layer 2)

CVE-2026-57019 HIGH
7.1 Jul 09

Denial-of-service in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series routers lets an unauth

CVE-2026-57021 MEDIUM
6.9 Jul 09

Out-of-bounds write in the Juniper Networks Junos OS http-gatekeeper (http-gk) process on SRX Series firewalls crashes t

CVE-2026-57024 MEDIUM
6.9 Jul 09

Repeated IKE negotiation failures on Juniper Junos OS (MX with SPC3 and SRX Series) cause a peer index rollover that ass

CVE-2026-57054 MEDIUM
6.9 Jul 09

Web filtering bypass on Juniper Networks Junos OS MX Series exposes downstream resources to unauthenticated network atta

CVE-2026-57025 MEDIUM
6.8 Jul 09

Denial-of-service in Juniper Networks Junos OS and Junos OS Evolved on EX Series, QFX Series, and MX Series allows a loc

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CVE-2026-57027 vulnerability details – vuln.today

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