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🛡️ CVE-2026-57027 — junos

🟡 CVSS 6.5 — Medium ✅ No Known Exploit CWE-401 NVD
6.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

How this vulnerability can be exploited

This issue can be reached from an adjacent network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

  • Attack vector: Adjacent network — the attacker has to sit on the same local or logical network.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-57027 is classified as CWE-401: Memory Leak. Allocated memory is never released, so long-running or repeated operations gradually exhaust it.

Affected software

CVE-2026-57027 is recorded against 1 package.

  • junos

Timeline and source

Published on 9 July 2026 and last revised on 13 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

supportportal.juniper.net

Other advisories for this package

junos has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-401: Memory Leak) in other software:

Details

Severity MEDIUM
CVSS Score 6.5
CVSS Vector CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-401
Public Exploit ✅ No
Source NVD
Published 2026-07-09
Updated 2026-08-20
Modified 2026-07-13
Fix URL N/A

Affected Packages

Software From version Fixed in
junos

References

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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