Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessEstablish/reach BGP adjacency to device
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ExploitSend crafted BGP route updates
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ExecutionTrigger out-of-bounds write in rpd
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ImpactCrash routing daemon (DoS)
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Exploitation requires the QFX5240, QFX5241, or QFX5250 to be explicitly configured for BGP global-load-balancing AND to have more than 128 ECMP next-hops - a specific, non-default operator configuration; devices without this configuration are not affected. The attacker must also have adjacent-network access as or on-path to a BGP peer (AV:A), not arbitrary remote internet access. No authentication is required per the vector (PR:N), and no user interaction is needed (UI:N). The combination of specific hardware, a specific routing feature configuration, and required BGP adjacency substantially limits the realistic exploitable population despite the unauthenticated vector. |
| Impact | This is a moderate-severity, availability-only denial-of-service flaw, not a high-priority emergency. The vendor CVSS 3.1 vector (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, 6.5) indicates an adjacent-network attacker with no privileges can crash the routing protocol daemon (rpd), but with zero confidentiality or integrity impact - the only consequence is a daemon crash (CWE-787 out-of-bounds write). Critically, exploitation is gated by a specific non-default configuration: BGP global-load-balancing enabled AND more than 128 ECMP next-hops, on a narrow set of QFX5240/5241/5250 hardware running Junos OS Evolved. No EPSS score, KEV listing, or public POC is present in the provided data, so there is no evidence of active exploitation or weaponization. The AV:A rating is consistent with the fact that an attacker would typically need to be an established/on-path BGP peer rather than an arbitrary internet host. In short: a real but narrow DoS requiring attacker adjacency plus a specific operator configuration - manageable priority, well below a critical RCE. No key signals conflict; the main gap is the absence of EPSS/KEV/POC data to confirm or rule out exploitation interest. |
| Exploit ScenarioDerived | An attacker positioned as (or on-path to) a BGP peer of a QFX5240/5241/5250 switch configured with global-load-balancing and more than 128 ECMP next-hops sends crafted BGP routing updates that trigger the out-of-bounds write in rpd. The resulting rpd crash disrupts routing on the affected device, causing a denial of service. No public exploit identified at time of analysis; the adjacent attack vector and dependence on a specific configuration limit practical reach. |
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Alert meAnalysisAIv1 – Oct 14, 2026
An out-of-bounds write in the routing protocol daemon (rpd) of Juniper Networks Junos OS Evolved on QFX5240, QFX5241, and QFX5250 switches configured for BGP global-load-balancing with more than 128 ECMP next-hops allows unauthenticated adjacent-network attackers to crash rpd, causing a denial of service. This moderate-severity (CVSS 6.5) flaw is availability-only; exploitation requires the specific hardware and non-default routing configuration, and no public exploit code has been identified at time of analysis. Devices not configured for BGP global-load-balancing or with 128 or fewer ECMP next-hops are not affected.
RemediationAI
Vendor-released patches are detailed in Juniper advisory JSA112250 (https://supportportal.juniper.net/JSA112250); apply the latest Junos OS Evolved release that addresses this issue. If immediate patching is not possible, operators can disable BGP global-load-balancing or reduce the number of ECMP next-hops to 128 or fewer as a workaround, but this may impact routing redundancy and load distribution. Additionally, restrict adjacent-network access to trusted BGP peers to limit exposure, though this is a general best practice. No public exploit code is known, and the vulnerability is availability-only.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The vulnerability resides in the routing protocol daemon (rpd) of Junos OS Evolved, which handles routing protocols including BGP. When BGP global-load-balancing is enabled and the number of ECMP next-hops exceeds 128, an out-of-bounds write (CWE-787) occurs, leading to memory corruption and a crash of rpd. The affected hardware models are QFX5240, QFX5241, and QFX5250. The CPE string cpe:2.3:a:juniper_networks:junos_os_evolved:*:*:*:*:*:*:*:* indicates that the vulnerability applies to Junos OS Evolved across versions, but only in the specific configuration. BGP global-load-balancing distributes traffic across multiple equal-cost paths; the 128 next-hop limit is a bound that, when exceeded, triggers the flaw. This is an availability issue only, as no confidentiality or integrity impact is assessed.
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Severity by source
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
Attacker needs BGP adjacency so AV:A; no auth or interaction (PR:N/UI:N); impact is limited to an rpd crash, so A:H with C:N/I:N.
Primary rating from Vendor (juniper).
CVSS VectorVendor: juniper
Lifecycle Timeline
3DescriptionCVE.org
An Out-of-bounds Write vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS Evolved on QFX5240, QFX5241 and QFX5250 configured for BGP global-load-balancing and more than 128 ecmp next-hops allows an attacker to cause an rpd crash.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
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EUVD-2026-101428
GHSA-75jw-fp45-jgrv
NVD
CVE.org
EPSS
Vulnrichment
Exploit-DB