In a DS-Lite (Dual-Stack Lite) and NAT (Network Address Translation) scenario, when crafted IPv6 traffic is received and prefix-length is set to 56, the ports assigned to the user will not be freed. Eventually, users cannot establish new connections. Affected FPC/PIC need to be manually restarted to recover.
Following is the command to identify the issue:
user@host> show services nat source port-block
Host_IP External_IP Port_Block Ports_Used/ Block_State/
Range Ports_Total Left_Time(s)
2001:: x.x.x.x 58880-59391 256/256*1 Active/- >>>>>>>>port still usedThis issue affects Junos OS on MX Series:
* from 21.2 before 21.2R3-S8,
* from 21.4 before 21.4R3-S7,
* from 22.1 before 22.1R3-S6,
* from 22.2 before 22.2R3-S4,
* from 22.3 before 22.3R3-S3,
* from 22.4 before 22.4R3-S2,
* from 23.2 before 23.2R2-S1,
* from 23.4 before 23.4R1-S2, 23.4R2.
This issue does not affect versions before 20.2R1.
Analysis and contextual insights are available on OpenCVE Cloud.
Vendor Solution
The following software releases have been updated to resolve this specific issue: Junos OS: 21.2R3-S8, 21.4R3-S7, 22.1R3-S6, 22.2R3-S4, 22.3R3-S3, 22.4R3-S2, 23.2R2-S1, 23.4R1-S2, 23.4R2, 24.2R1, and all subsequent releases.
Vendor Workaround
Modify the IPv6 prefix-length to be 64/96/128 through the command: [ set services service-set <*> softwire-options dslite-ipv6-prefix-length 64/96/128]
Tracking
Sign in to view the affected projects.
| Source | ID | Title |
|---|---|---|
EUVD |
EUVD-2025-10531 | An Improper Check for Unusual or Exceptional Conditions vulnerability in the pfe (packet forwarding engine) of Juniper Networks Junos OS on MX Series causes a port within a pool to be blocked leading to Denial of Service (DoS). In a DS-Lite (Dual-Stack Lite) and NAT (Network Address Translation) scenario, when crafted IPv6 traffic is received and prefix-length is set to 56, the ports assigned to the user will not be freed. Eventually, users cannot establish new connections. Affected FPC/PIC need to be manually restarted to recover. Following is the command to identify the issue: user@host> show services nat source port-block Host_IP External_IP Port_Block Ports_Used/ Block_State/ Range Ports_Total Left_Time(s) 2001:: x.x.x.x 58880-59391 256/256*1 Active/- >>>>>>>>port still usedThis issue affects Junos OS on MX Series: * from 21.2 before 21.2R3-S8, * from 21.4 before 21.4R3-S7, * from 22.1 before 22.1R3-S6, * from 22.2 before 22.2R3-S4, * from 22.3 before 22.3R3-S3, * from 22.4 before 22.4R3-S2, * from 23.2 before 23.2R2-S1, * from 23.4 before 23.4R1-S2, 23.4R2. This issue does not affect versions before 20.2R1. |
| Link | Providers |
|---|---|
| https://supportportal.juniper.net/JSA96449 |
|
Mon, 26 Jan 2026 19:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Juniper
Juniper junos Juniper mx10004 Juniper mx10008 Juniper mx2008 Juniper mx2010 Juniper mx2020 Juniper mx204 Juniper mx240 Juniper mx304 Juniper mx480 Juniper mx960 |
|
| CPEs | cpe:2.3:h:juniper:mx10004:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx10008:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx2008:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx2010:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx2020:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx204:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx240:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx304:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx480:-:*:*:*:*:*:*:* cpe:2.3:h:juniper:mx960:-:*:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:-:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r1-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r1-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r2-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r2-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r3-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r3-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r3-s3:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r3-s4:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r3-s5:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r3-s6:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r3-s7:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.2:r3:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:-:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r1-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r1-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r2-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r2-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r3-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r3-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r3-s3:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r3-s4:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r3-s5:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r3-s6:*:*:*:*:*:* cpe:2.3:o:juniper:junos:21.4:r3:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:-:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r1-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r1-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r2-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r2-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r3-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r3-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r3-s3:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r3-s4:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r3-s5:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.1:r3:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:-:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:r1-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:r1-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:r1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:r2-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:r2-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:r2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:r3-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:r3-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:r3-s3:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.2:r3:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.3:-:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.3:r1-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.3:r1-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.3:r1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.3:r2-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.3:r2-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.3:r2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.3:r3-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.3:r3-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.3:r3:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.4:-:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.4:r1-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.4:r1-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.4:r1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.4:r2-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.4:r2-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.4:r2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.4:r3-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:22.4:r3:*:*:*:*:*:* cpe:2.3:o:juniper:junos:23.2:-:*:*:*:*:*:* cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:23.2:r2:*:*:*:*:*:* cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:* cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:* cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:* |
|
| Vendors & Products |
Juniper
Juniper junos Juniper mx10004 Juniper mx10008 Juniper mx2008 Juniper mx2010 Juniper mx2020 Juniper mx204 Juniper mx240 Juniper mx304 Juniper mx480 Juniper mx960 |
Thu, 10 Apr 2025 14:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Wed, 09 Apr 2025 20:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | An Improper Check for Unusual or Exceptional Conditions vulnerability in the pfe (packet forwarding engine) of Juniper Networks Junos OS on MX Series causes a port within a pool to be blocked leading to Denial of Service (DoS). In a DS-Lite (Dual-Stack Lite) and NAT (Network Address Translation) scenario, when crafted IPv6 traffic is received and prefix-length is set to 56, the ports assigned to the user will not be freed. Eventually, users cannot establish new connections. Affected FPC/PIC need to be manually restarted to recover. Following is the command to identify the issue: user@host> show services nat source port-block Host_IP External_IP Port_Block Ports_Used/ Block_State/ Range Ports_Total Left_Time(s) 2001:: x.x.x.x 58880-59391 256/256*1 Active/- >>>>>>>>port still usedThis issue affects Junos OS on MX Series: * from 21.2 before 21.2R3-S8, * from 21.4 before 21.4R3-S7, * from 22.1 before 22.1R3-S6, * from 22.2 before 22.2R3-S4, * from 22.3 before 22.3R3-S3, * from 22.4 before 22.4R3-S2, * from 23.2 before 23.2R2-S1, * from 23.4 before 23.4R1-S2, 23.4R2. This issue does not affect versions before 20.2R1. | |
| Title | Junos OS: MX Series: In DS-lite and NAT scenario receipt of crafted IPv6 traffic causes port block | |
| Weaknesses | CWE-754 | |
| References |
| |
| Metrics |
cvssV3_1
|
Status: PUBLISHED
Assigner: juniper
Published:
Updated: 2025-04-10T13:14:00.650Z
Reserved: 2024-12-26T14:47:11.669Z
Link: CVE-2025-21594
Updated: 2025-04-10T13:13:56.855Z
Status : Analyzed
Published: 2025-04-09T20:15:25.620
Modified: 2026-01-26T19:36:10.717
Link: CVE-2025-21594
No data.
OpenCVE Enrichment
Updated: 2025-07-13T11:07:17Z
EUVD