Junos OS Evolved: shell-injection vulnerabilities in evo_sftp UI wrapper script
A command injection vulnerability in sftp command processing on Juniper Networks Junos OS Evolved allows an attacker with authenticated CLI access to be able to bypass configured access protections to execute arbitrary shell commands within the context of the current user. The vulnerability allows an attacker to bypass command authorization restrictions assigned to their specific user account and execute commands that are available to the privilege level for which the user is assigned. For example, a user that is in the super-user login class, but restricted to executing specific CLI commands could exploit the vulnerability to execute any other command available to an unrestricted admin user. This vulnerability does not increase the privilege level of the user, but rather bypasses any CLI command restrictions by allowing full access to the shell. This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-S2-EVO; 21.1 versions prior to 21.1R2-EVO; 21.2 versions prior to 21.2R1-S1-EVO, 21.2R2-EVO.
- Published
- Oct 19, 2021
- Updated
- Jun 16, 2026
- EPSS
- 0.6% · 48th percentile
- CWE
- CWE-77
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CNA vs NVD score
- NVD
- —
- CNA · juniper
- 7.8
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| juniper | junos os evolved | cpe:2.3:o:juniper:junos_os_evolved |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- juniper junos os evolvedup to 20.3 inclusive
- juniper junos os evolved20.4
- juniper junos os evolved21.1
- juniper junos os evolved21.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (juniper). Independent of NVD's CPE analysis and usually ahead of it.
Juniper Networks Junos OS Evolved
- unspecified and later · before 20.4R2-S2-EVOaffected
- 21.1 and later · before 21.1R2-EVOaffected
- 21.2 and later · before 21.2R1-S1-EVO, 21.2R2-EVOaffected
Same product
juniper: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-21902Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root42Plan
- CVE-2023-28983Junos OS Evolved: Shell Injection vulnerability in the gNOI server35Monitor
- CVE-2022-22239Junos OS Evolved: The ssh CLI command always runs as root which can lead to privilege escalation35Monitor
- CVE-2026-33788Junos OS Evolved: Local, authenticated attacker can gain privileged access to FPCs34Monitor
- CVE-2025-52954Junos OS Evolved: A low-privileged user can execute arbitrary Junos commands and modify the configuration, thereby compromising the system34Monitor
- CVE-2025-21599Junos OS Evolved: Receipt of specifically malformed IPv6 packets causes kernel memory exhaustion leading to Denial of Service34Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-77 · Improper Neutralization of Special Elements used in a Command ('Command Injection')CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- LDAP InjectionCAPEC-136likelihood: High · High
- Command DelimitersCAPEC-15likelihood: High · High
- IMAP/SMTP Command InjectionCAPEC-183Medium
- Command InjectionCAPEC-248likelihood: Medium · High
- Manipulating Writeable Terminal DevicesCAPEC-40likelihood: High · Very High
- Exploiting Multiple Input Interpretation LayersCAPEC-43likelihood: Medium · High
- Manipulating Writeable Configuration FilesCAPEC-75likelihood: High · Very High
- Manipulating Web Input to File System CallsCAPEC-76likelihood: High · Very High
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.