EUVD-2026-42713
GHSA-q958-7f7x-pmq4
Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/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
Local CLI access and a low-privileged account are required; only availability is impacted via temporary process crash with no confidentiality or integrity effect.
Primary rating from Vendor (juniper).
CVSS VectorVendor: juniper
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/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
Lifecycle Timeline
3DescriptionCVE.org
A Return of Pointer Value Outside of Expected Range vulnerability in the fileio library of Juniper Networks Junos OS and Junos OS Evolved allows a local, low-privilged attacker to cause a Denial-of-Service (DoS).
On EX Series, QFX Series and MX Series a low-privileged attacker issuing a specific 'show l2-learning' command will cause an l2ald crash which will lead to a temporary service impact for all layer 2 services until the process has automatically restarted.
This issue affects EX Series, QFX Series, MX Series: Junos OS:
- all versions before 23.2R2-S7,
- 23.4 versions before 23.4R2-S7,
- 24.2 versions before 24.2R2,
- 24.4 versions before 24.4R1-S2.
Junos OS Evolved:
- all versions before 23.2R2-S7-EVO,
- 23.4 versions before 23.4R2-S8-EVO,
- 24.2 versions before 24.2R2-EVO,
- 24.4 versions before 24.4R1-S3-EVO.
AnalysisAI
Denial-of-service in Juniper Networks Junos OS and Junos OS Evolved on EX Series, QFX Series, and MX Series allows a local, low-privileged attacker to crash the l2ald (Layer 2 Address Learning Daemon) by issuing a specific 'show l2-learning' CLI command, disrupting all Layer 2 services until the process automatically restarts. The root cause is a Return of Pointer Value Outside of Expected Range flaw (CWE-466) in the fileio library. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires local CLI access to the affected Juniper device (AV:L confirmed by CVSS vector), which in practice means SSH, console, or out-of-band management access. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 base score of 5.5 (Medium) accurately reflects the constrained attack surface: AV:L requires the attacker to have local CLI access to the device, and PR:L requires at least a low-privileged account - meaning unauthenticated remote exploitation is not possible. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker with a low-privileged Junos CLI account - for example, a read-only NOC operator account or a compromised service account - logs into an affected EX, QFX, or MX device via SSH and issues a specific 'show l2-learning' command. This triggers the pointer out-of-range condition in the fileio library, crashing l2ald and dropping all Layer 2 forwarding state on the device until the process restarts, potentially causing network outages for downstream users. … |
| Remediation | The primary fix is to upgrade to a patched Junos OS release. … Detailed patch versions, workarounds, and compensating controls in full report. |
Threat intelligence, references, and detailed analysis are available after sign-in.
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Same technique Denial Of Service
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External POC / Exploit Code
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