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Full vulnerability report · 2025
CVE-2025-21595High confidence

Junos OS and Junos OS Evolved: In an EVPN-VXLAN scenario specific ARP or NDP packets cause FPC to crash

Juniper Networks · Junos OS

7.1HighCVSS 4.0
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.26% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Juniper Networks Junos OS and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2025-10527

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

A Missing Release of Memory after Effective Lifetime vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause an FPC to crash, leading to Denial of Service (DoS). On all Junos OS and Junos OS Evolved platforms, in an EVPN-VXLAN scenario, when specific ARP packets are received on an IPv4 network, or specific NDP packets are received on an IPv6 network, kernel heap memory leaks, which eventually leads to an FPC crash and restart. This issue does not affect MX Series platforms. Heap size growth on FPC can be seen using below command. user@host> show chassis fpc                     Temp CPU Utilization (%) CPU Utilization (%) Memory   Utilization (%) Slot State           (C) Total Interrupt     1min   5min   15min   DRAM (MB)   Heap   Buffer   0 Online           45     3         0       2       2      2       32768      19       0 <<<<<<< Heap increase in all fPCs This issue affects Junos OS: * All versions before 21.2R3-S7, * 21.4 versions before 21.4R3-S4, * 22.2 versions before 22.2R3-S1,  * 22.3 versions before 22.3R3-S1,  * 22.4 versions before 22.4R2-S2, 22.4R3. and Junos OS Evolved: * All versions before 21.2R3-S7-EVO, * 21.4-EVO versions before 21.4R3-S4-EVO, * 22.2-EVO versions before 22.2R3-S1-EVO,  * 22.3-EVO versions before 22.3R3-S1-EVO,  * 22.4-EVO versions before 22.4R3-EVO.

What

A Missing Release of Memory after Effective Lifetime vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause an FPC to crash, leading to Denial of Service (DoS). On all Junos OS and Junos OS Evolved platforms, in an EVPN-VXLAN scenario, when specific ARP packets are received on an IPv4 network, or specific NDP packets are received on an IPv6 network, kernel heap memory leaks, which eventually leads to an FPC crash and restart. This issue does not affect MX Series platforms. Heap size growth on FPC can be seen using below command. user@host> show chassis fpc                     Temp CPU Utilization (%) CPU Utilization (%) Memory   Utilization (%) Slot State           (C) Total Interrupt     1min   5min   15min   DRAM (MB)   Heap   Buffer   0 Online           45     3         0       2       2      2       32768      19       0 <<<<<<< Heap increase in all fPCs This issue affects Junos OS: * All versions before 21.2R3-S7, * 21.4 versions before 21.4R3-S4, * 22.2 versions before 22.2R3-S1,  * 22.3 versions before 22.3R3-S1,  * 22.4 versions before 22.4R2-S2, 22.4R3. and Junos OS Evolved: * All versions before 21.2R3-S7-EVO, * 21.4-EVO versions before 21.4R3-S4-EVO, * 22.2-EVO versions before 22.2R3-S1-EVO,  * 22.3-EVO versions before 22.3R3-S1-EVO,  * 22.4-EVO versions before 22.4R3-EVO.

Why

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

A Missing Release of Memory after Effective Lifetime vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause an FPC to crash, leading to Denial of Service (DoS). On all Junos OS and Junos OS Evolved platforms, in an EVPN-VXLAN scenario, when specific ARP packets are received on an IPv4 network, or specific NDP packets are received on an IPv6 network, kernel heap memory leaks, which eventually leads to an FPC crash and restart. This issue does not affect MX Series platforms. Heap size growth on FPC can be seen using below command. user@host> show chassis fpc                     Temp CPU Utilization (%) CPU Utilization (%) Memory   Utilization (%) Slot State           (C) Total Interrupt     1min   5min   15min   DRAM (MB)   Heap   Buffer   0 Online           45     3         0       2       2      2       32768      19       0 <<<<<<< Heap increase in all fPCs This issue affects Junos OS: * All versions before 21.2R3-S7, * 21.4 versions before 21.4R3-S4, * 22.2 versions before 22.2R3-S1,  * 22.3 versions before 22.3R3-S1,  * 22.4 versions before 22.4R2-S2, 22.4R3. and Junos OS Evolved: * All versions before 21.2R3-S7-EVO, * 21.4-EVO versions before 21.4R3-S4-EVO, * 22.2-EVO versions before 22.2R3-S1-EVO,  * 22.3-EVO versions before 22.3R3-S1-EVO,  * 22.4-EVO versions before 22.4R3-EVO.

Why

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
an adjacent network → Missing Release of Memory after Effective Lifetime → disrupt the affected service
Attack surface
Adjacent
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-401 ↗

CWE-401: Missing Release of Memory after Effective Lifetime. The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
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

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVAdjacentAttack vector: The attacker must be on an adjacent or logically close network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SALowSubsequent-system availability: A successful attack can cause a limited loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
UnauthenticatedDenial of serviceCWE-401
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2025-0777Juniper JUNOS: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Juniper JUNOS ausnutzen, um einen Denial-of-Service-Zustand herbeizuführen, vertrauliche Informationen preiszugeben und möglicherweise beliebigen Code auszuführen.

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0304Multiples vulnérabilités dans les produits Juniper Networks

tal.juniper.net/s/article/2025-04-Security-Bulletin-Junos-OS-An-unauthenticated-adjacent-attacker-sending-a-malformed-DHCP-packet-causes-jdhcpd-to-crash-CVE-2025-21591 Bulletin de sécurité Juniper Networks JSA96449 du 09 avril 2025 https://supportportal.juniper.net/s/article/2025-04-Security-Bulletin-Junos-OS-MX-Series-In-DS-lite-and-NAT-senario-receipt-of-crafted-IPv4-traffic-causes-port-block-CVE-2025-21594 Bulletin de sécurité Juniper Networks JSA96450 du 09 avril 2025 https://supportportal.juniper.net/s/article/2025-04-Security-Bulletin-Junos-OS-and-Junos-OS-Evolved-In-an-EVPN-VXLAN-scenario-specific-ARP-or-NDP-packets-cause-FPC-to-crash-CVE-2025-21595 Bulletin de sécurité Juniper Networks JSA96451 du 09 avril 2025 https://supportportal.juniper.net/s/article/2025-04-Security-Bulletin-Junos-OS-and-Junos-OS-Evolved-When-BGP-rib-sharding-and-update-threading-are-configured-and-a-peer-flaps-an-rpd-core-is-observed Bulletin de sécurité Juniper Networks JSA96452 du 09 avril 2025 https://supportportal.juniper.net/s/article/2025-04-Security-Bulletin-Junos-OS-SRX-and-EX-Series-MX240-MX480-MX960-QFX5120-Series-When-web-management-is-enabled-for-specific-services-an-attacker-may-cause-a-CPU-spike-by-sending-genuine-packets-to-the-device-CVE-2025-21601 Bulletin de sécurité Juniper Networks JSA96453 du

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2025-025424ジュニパーネットワークスのJunos OS等の複数製品における有効期限後のメモリの解放の欠如に関する脆弱性

Juniper Networks Junos OSおよびJunos OS Evolvedのパケット転送エンジン（PFE）において、有効寿命後のメモリ解放不足の脆弱性が存在します。この脆弱性により、隣接する認証されていない攻撃者がFPCをクラッシュさせ、サービス拒否（DoS）を引き起こす可能性があります。すべてのJunos OSおよびJunos OS Evolvedプラットフォームでは、EVPN-VXLAN環境で特定のARPパケットがIPv4ネットワーク上で受信されたり、特定のNDPパケットがIPv6ネットワーク上で受信されたりすると、カーネルヒープメモリがリークし、最終的にFPCがクラッシュして再起動します。この問題はMXシリーズプラットフォームには影響しません。FPCのヒープサイズの増加は、以下のコマンドで確認できます。user@host show chassis fpc；このコマンドを実行すると、Temp、CPU利用率（％）、メモリ利用率（％）、スロット、状態、合計、割り込み、1分、5分、15分、DRAM（MB）、ヒープ、バッファなどの情報が表示され、すべてのFPCでヒープ増加が確認されます。この問題は以下のJunos OSバージョンに影響します。21.2R3-S7以前のすべてのバージョン、21.4バージョンの21.4R3-S4以前、22.2バージョンの22.2R3-S1以前、22.3バージョンの22.3R3-S1以前、22.4バージョンの22.4R2-S2および22.4R3以前です。同様に、Junos OS Evolvedのすべてのバージョンでは、21.2R3-S7-EVO以前、21.4-EVOの21.4R3-S4-EVO以前、22.2-EVOの22.2R3-S1-EVO以前、22.3-EVOの22.3R3-S1-EVO以前、および22.4-EVOの22.4R3-EVO以前に影響を及ぼします。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 9 Apr 2025 · Last source change 10 Apr 2025, 13:13 UTC · CWE-401 · Missing Release of Memory after Effective Lifetime

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2025-10527
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2025-10527↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2025-21595 · cve.blacktree.nl