Junos OS: Incorrect Permission Assignment for Critical Resource
CVE-2025-30661 is a high-severity incorrect permission assignment for critical resource vulnerability in Junos OS from Juniper Networks, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, but only if a user takes part, for example by opening a link or file. The record lists versions 23.2R2-S4, 23.4R2-S5, 24.2R2-S1 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 0.2% 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-S4 or 23.4R2-S5 or 24.2R2-S1 or 24.4R1-S3, 24.4R2, whichever matches your release line, or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Juniper Networks | Junos OS | 23.2 up to, but not including, 23.2R2-S4; 23.4 up to, but not including, 23.4R2-S5; 24.2 up to, but not including, 24.2R2-S1; 24.4 up to, but not including, 24.4R1-S3, 24.4R2 | 23.2R2-S4, 23.4R2-S5, 24.2R2-S1, 24.4R1-S3, 24.4R2 |
| Juniper Networks | Junos | 23.2; 23.4; 24.2; 24.4 | Not stated |
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H. Scored by CNA (juniper.net).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.5 | High | CNA (juniper.net) |
| CVSS 3.1 | 7.3 | High | CNA (juniper.net) |
Official description
An Incorrect Permission Assignment for Critical Resource vulnerability in line card script processing of Juniper Networks Junos OS allows a local, low-privileged user to install scripts to be executed as root, leading to privilege escalation. A local user with access to the local file system can copy a script to the router in a way that will be executed as root, as the system boots. Execution of the script as root can lead to privilege escalation, potentially providing the adversary complete control of the system. This issue only affects specific line cards, such as the MPC10, MPC11, LC4800, LC9600, MX304-LMIC16, SRX4700, and EX9200-15C. This issue affects Junos OS: * from 23.2 before 23.2R2-S4, * from 23.4 before 23.4R2-S5, * from 24.2 before 24.2R2-S1, * from 24.4 before 24.4R1-S3, 24.4R2. This issue does not affect versions prior to 23.1R2.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Permission Assignment for Critical Resource
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
How developers prevent this class of flaw
- When using a critical resource such as a configuration file, check to see if the resource has insecure permissions (such as being modifiable by any regular user), and generate an error or even exit the software if there is a possibility that the resource could have been modified by an unauthorized party.
- Divide the software into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully defining distinct user groups, privileges, and/or roles. Map these against data, functionality, and the related resources. Then set the permissions accordingly. This will allow you to maintain more fine-grained control over your resources.
- During program startup, explicitly set the default permissions or umask to the most restrictive setting possible. Also set the appropriate permissions during program installation. This will prevent you from inheriting insecure permissions from any user who installs or runs the program.
More Incorrect Permission Assignment for Critical Resource vulnerabilities (CWE-732)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
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 Incorrect Permission Assignment for Critical Resource vulnerabilities
- 7.8 High severity
- 7.0 High severity
- 9.9 Critical severity
- 7.3 High severity
- 8.0 High severity
- 7.1 High severity
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