Junos OS: Improper Validation of Consistency within Input
CVE-2026-101951 is a high-severity improper validation of consistency within input vulnerability in Junos OS from Juniper Networks, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5 as the first without the flaw, so updating Junos OS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.44% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Junos OS to 23.2R2-S7.7 or 23.4R2-S8.13 or 24.2R2-S5.5 or 24.4R2-S5, whichever matches your release line, or a later version.
- Update Junos OS Evolved to 23.2R2-S7.7-EVO or 23.4R2-S8.11-EVO or 24.2R2-S5.6-EVO or 24.4R2-S5-EVO, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Juniper Networks | Junos OS | before 23.2R2-S7.7; 23.4 up to, but not including, 23.4R2-S8.13; 24.2 up to, but not including, 24.2R2-S5.5; 24.4 up to, but not including, 24.4R2-S5; 25.2 up to, but not including, 25.2R2-S2; 25.4 up to, but not including, 25.4R1-S3; 26.2 up to, but not including, 26.2R1-S2 | 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3 |
| Juniper Networks | Junos OS Evolved | before 23.2R2-S7.7-EVO; 23.4 up to, but not including, 23.4R2-S8.11-EVO; 24.2 up to, but not including, 24.2R2-S5.6-EVO; 24.4 up to, but not including, 24.4R2-S5-EVO; 25.2 up to, but not including, 25.2R2-S2-EVO; 25.4 up to, but not including, 25.4R1-S3-EVO; 26.2 up to, but not including, 26.2R1-S2-EVO; 23.4X100; and 2 more ranges | 23.2R2-S7.7-EVO, 23.4R2-S8.11-EVO, 24.2R2-S5.6-EVO, 24.4R2-S5-EVO, 25.2R2-S2-EVO, 25.4R1-S3-EVO |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (juniper.net).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (juniper.net) |
| CVSS 3.1 | 7.5 | High | CNA (juniper.net) |
Official description
An Improper Validation of Consistency within Input vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-adjacent configured BGP peer to cause a denial of service by sending a specifically malformed BGP MCAST-TREE update and this NLRI is then attempted to be readvertised.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Validation of Consistency within Input
The product receives a complex input with multiple elements or fields that must be consistent with each other, but it does not validate or incorrectly validates that the input is actually consistent.
More Improper Validation of Consistency within Input vulnerabilities (CWE-1288)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Junos OS
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 7.5 High severity
Recent Improper Validation of Consistency within Input vulnerabilities
- 8.2 High severity
- 8.7 High severity
- 7.5 High severity
- 7.1 High severity
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