VulnerabilityPublished 9 Oct 2025

CVE-2025-52961: Juniper Networks Junos OS Evolved · Uncontrolled Resource Consumption

Affects Juniper Networks Junos OS EvolvedSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 09:15 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Adjacent
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Juniper Networks Junos OS Evolved	Affected =23.4-EVO =24.2-EVO =24.4-EVO	Fixed in–

AI-suggested

1. Upgrade affected Junos OS Evolved versions to fixed releases once available from Juniper Networks, as no patches are currently listed but should be prioritized upon release. 2. Implement strict network segmentation and access controls to limit adjacency and prevent unauthorized devices from sending CFM traffic to critical routers. 3. Monitor cfmman process memory usage regularly using the command 'show system processes node fpc<num> detail | match cfmman' to detect abnormal RSS growth indicative of exploitation attempts. 4. Consider automated alerts for unusual CPU spikes on cfmd and memory leaks on cfmman to enable rapid incident response. 5. Temporarily, restarting the affected device can clear memory leaks but is not a long-term solution. 6. Employ network anomaly detection systems capable of identifying unusual CFM traffic patterns. 7. Coordinate with Juniper support for guidance and early access to patches or workarounds. 8. Review and harden adjacent network segments to reduce exposure to unauthenticated traffic targeting CFM services. 9. Document and test incident response plans specifically for network device DoS scenarios to minimize downtime.

Description

An Uncontrolled Resource Consumption vulnerability in the Connectivity Fault Management (CFM) daemon and the Connectivity Fault Management Manager (cfmman) of Juniper Networks Junos OS Evolved on PTX10001-36MR, PTX10002-36QDD, PTX10004, PTX10008, PTX10016 allows an unauthenticated, adjacent attacker to cause a Denial-of-Service (DoS). An attacker on an adjacent device sending specific valid traffic can cause cfmd to spike the CPU to 100% and cfmman's memory to leak, eventually to cause the FPC crash and restart. Continued receipt and processes of these specific valid packets will sustain the Denial of Service (DoS) condition. An indicator of compromise is to watch for an increase in cfmman memory rising over time by issuing the following command and evaluating the RSS number. If the RSS is growing into GBs then consider restarting the device to temporarily clear memory. user@device> show system processes node fpc<num> detail | match cfmman Example: show system processes node fpc0 detail | match cfmman F S UID PID PPID PGID SID C PRI NI ADDR SZ WCHAN RSS PSR STIME TTY TIME CMD 4 S root 15204 1 15204 15204 0 80 0 - 90802 - 113652 4 Sep25 ? 00:15:28 /usr/bin/cfmman -p /var/pfe -o -c /usr/conf/cfmman-cfg-active.xml This issue affects Junos OS Evolved on PTX10001-36MR, PTX10002-36QDD, PTX10004, PTX10008, PTX10016: * from 23.2R1-EVO before 23.2R2-S4-EVO, * from 23.4 before 23.4R2-S4-EVO, * from 24.2 before 24.2R2-EVO, * from 24.4 before 24.4R1-S2-EVO, 24.4R2-EVO. This issue does not affect Junos OS Evolved on PTX10001-36MR, PTX10002-36QDD, PTX10004, PTX10008, PTX10016 before 23.2R1-EVO.

Impact

European organizations relying on Juniper PTX series routers running affected Junos OS Evolved versions face potential network disruptions due to this vulnerability. The Denial-of-Service condition can cause critical network infrastructure components to crash and restart, leading to temporary loss of routing and connectivity services. This can impact ISPs, data centers, large enterprises, and telecom providers that use these routers for backbone or edge routing. The lack of authentication requirement and the ability to exploit from an adjacent network segment increase the risk, especially in environments with less segmented or poorly controlled network access. Sustained DoS attacks could degrade service availability, affecting business continuity and potentially violating regulatory requirements for network uptime and reliability. The vulnerability could also be leveraged as part of a larger attack chain targeting network infrastructure. While no known exploits exist yet, the medium CVSS score and the critical role of affected devices underscore the importance of timely mitigation.

Summary

CVE-2025-52961 is a resource exhaustion vulnerability classified under CWE-400 affecting Juniper Networks Junos OS Evolved on specific PTX series routers. The flaw resides in the Connectivity Fault Management (CFM) daemon (cfmd) and the Connectivity Fault Management Manager (cfmman). An attacker located on an adjacent network segment can exploit this by sending specially crafted but valid CFM packets that cause the cfmd process to spike CPU usage to 100% and cause cfmman to leak memory continuously. Over time, this resource exhaustion leads to the failure and restart of the Flexible PIC Concentrator (FPC), effectively causing a Denial-of-Service (DoS) condition. The attack requires no authentication or user interaction, making it easier to exploit in environments where adjacent network access is possible. The vulnerability affects Junos OS Evolved versions starting from 23.2R1-EVO up to 24.4R2-EVO on PTX10001-36MR, PTX10002-36QDD, PTX10004, PTX10008, and PTX10016 hardware platforms. Operators can monitor the memory usage of cfmman using system commands to detect abnormal growth in resident set size (RSS), which can reach gigabytes before a crash occurs. No patches or exploit code are currently publicly available, but the vulnerability is officially published and tracked with a CVSS v3.1 score of 6.5, indicating a medium severity level primarily due to the impact on availability. The vulnerability does not affect versions prior to 23.2R1-EVO.

CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Regular Expression Exponential Blowup (opens in a new tab)
Sustained Client Engagement (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 9 Oct 2025, 16:10 UTC

WeaknessesCWE-400

Technical details

References

Community reviews

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