CVE-2025-52946VulnerabilityPublished 11 Jul 2025

CVE-2025-52946: Juniper Networks Junos OS · Use After Free

Affects Juniper Networks Junos OSSource CVE Database V5

Mentioned vulnerabilities

CVE-2024-39549

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 08:11 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
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: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
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 11 Jul 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	Affected =0 =21.4 =22.2 =22.4 =23.2 =23.4 =24.2	Fixed in–

AI-suggested

1. Immediate action should be to verify if BGP traceoptions are enabled on Juniper devices running affected Junos OS versions. If traceoptions are not required for active troubleshooting, disable them to eliminate exposure. 2. Apply the latest Juniper patches or software updates that address CVE-2025-52946 as soon as they become available. Since this vulnerability affects multiple Junos OS and Junos OS Evolved versions, coordinate with Juniper support to obtain the appropriate fixed releases. 3. Implement network segmentation and strict access controls to limit which peers can establish BGP sessions, reducing the risk of malicious BGP updates from untrusted sources. 4. Monitor BGP session stability and rpd process logs for signs of crashes or restarts, which may indicate exploitation attempts. 5. Employ anomaly detection systems to identify malformed BGP updates or unusual AS PATH attributes. 6. For environments requiring traceoptions, consider enabling them only temporarily during controlled troubleshooting windows and disable immediately afterward. 7. Engage with Juniper Networks for guidance on best practices for secure BGP configuration and traceoptions usage. 8. Review and update incident response plans to include procedures for handling routing daemon crashes and potential DoS attacks targeting network infrastructure.

Description

A Use After Free vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Juniper Networks Junos OS Evolved allows an attacker sending a BGP update with a specifically malformed AS PATH to cause rpd to crash, resulting in a Denial of Service (DoS). Continuous receipt of the malformed AS PATH attribute will cause a sustained DoS condition. On all Junos OS and Junos OS Evolved platforms, the rpd process will crash and restart when a specifically malformed AS PATH is received within a BGP update and traceoptions are enabled. This issue only affects systems with BGP traceoptions enabled and requires a BGP session to be already established. Systems without BGP traceoptions enabled are not impacted by this issue. This issue affects: Junos OS: * All versions before 21.2R3-S9, * all versions of 21.4, * from 22.2 before 22.2R3-S6, * from 22.4 before 22.4R3-S5, * from 23.2 before 23.2R2-S3, * from 23.4 before 23.4R2-S4, * from 24.2 before 24.2R2; Junos OS Evolved: * All versions before 22.4R3-S5-EVO, * from 23.2-EVO before 23.2R2-S3-EVO, * from 23.4-EVO before 23.4R2-S4-EVO, * from 24.2-EVO before 24.2R2-EVO. This is a more complete fix for previously published CVE-2024-39549 (JSA83011).

Impact

For European organizations, this vulnerability can have serious implications on network availability and operational continuity. Juniper Networks devices are widely deployed in enterprise, service provider, and critical infrastructure networks across Europe. An attacker exploiting this vulnerability could cause repeated crashes of the routing daemon, leading to intermittent or sustained network outages. This can disrupt internal communications, internet connectivity, and inter-domain routing, potentially affecting business operations, cloud services access, and critical communications. The impact is especially critical for telecom operators, ISPs, and large enterprises that depend on stable BGP routing for their network backbone. Additionally, the requirement for an established BGP session means that attackers with network access or compromised peers could exploit this vulnerability remotely without authentication or user interaction. This raises concerns for multi-tenant data centers and peering arrangements common in European networks. While no confidentiality or integrity impacts are noted, the availability impact alone can cause significant financial and reputational damage. The presence of traceoptions enabled in production environments, often for troubleshooting, increases the attack surface. European organizations must be aware of this risk, particularly those with Juniper infrastructure running affected Junos OS versions and BGP traceoptions enabled.

CWE-416Use After Free (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #7
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Architecture and Design · Language Selection
Choose a language that provides automatic memory management.
Implementation · Attack Surface Reduction
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

supportportal.juniper.net/JSA100050 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Jul 2025, 16:01 UTC

WeaknessesCWE-416

Technical details

References

Community reviews

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