Medium Injection

CVE-2026-33791 — Junos OS and Junos OS Evolved: Execution of crafted CLI commands allows for arbitrary shell injection as root

An OS Command Injection vulnerability in the CLI processing of Juniper Networks Junos OS and Junos OS Evolved allows a local, high-privileged attacker executing specific, crafted CLI commands to inject arbitrary shell commands as root, leading to a complete compromise of the system. Certain 'set system' commands, when executed with crafted arguments, are not properly sanitized, allowing for arbitrary shell injection. These shell commands are executed as root, potentially allowing for complete control of the vulnerable system. This issue affects: Junos OS: * all versions before 22.4R3-S8, * from 23.2 before 23.2R2-S5, * from 23.4 before 23.4R2-S7, * from 24.2 before 24.2R2-S2, * from 24.4 before 24.4R2, * from 25.2 before 25.2R2; Junos OS Evolved: * all versions before 22.4R3-S8-EVO, * from 23.2 before 23.2R2-S5-EVO, * from 23.4 before 23.4R2-S7-EVO, * from 24.2 before 24.2R2-S2-EVO, * from 24.4 before 24.4R2-EVO, * from 25.2 before 25.2R1-S1-EVO, 25.2R2-EVO.

Published Apr 9, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: juniper

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.7% (30-day exploitation probability)+8
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.67%

ahead of 51% of scored CVEs · Oct 14, 2026

Affects

Juniper Networks

Junos and 2 more

CVSS base

6.7

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented mitigation — kb.juniper.net (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Juniper Networks Junos, Juniper Networks Junos OS, Juniper Networks Junos Os Evolved).
Apply the documented mitigations until a definitive fix is available.
Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Juniper Networks	Junos	< 22.4version 22.4version 22.4-r1version 22.4-r1-s1version 22.4-r1-s2version 22.4-r2version 22.4-r2-s1version 22.4-r2-s2 and 42 more version 22.4-r3version 22.4-r3-s1version 22.4-r3-s2version 22.4-r3-s3version 22.4-r3-s4version 22.4-r3-s5version 22.4-r3-s6version 22.4-r3-s7version 23.2version 23.2-r1version 23.2-r1-s1version 23.2-r1-s2version 23.2-r2version 23.2-r2-s1version 23.2-r2-s2version 23.2-r2-s3version 23.2-r2-s4version 23.4version 23.4-r1version 23.4-r1-s1version 23.4-r1-s2version 23.4-r2version 23.4-r2-s1version 23.4-r2-s2version 23.4-r2-s3version 23.4-r2-s4version 23.4-r2-s5version 23.4-r2-s6version 24.2version 24.2-r1version 24.2-r1-s1version 24.2-r1-s2version 24.2-r2version 24.2-r2-s1version 24.4version 24.4-r1version 24.4-r1-s2version 24.4-r1-s3version 25.2version 25.2-r1version 25.2-r1-s1version 25.2-r1-s2	Vulnerable	NIST National Vulnerability Database
Juniper Networks	Junos OS	< 22.4R3-S8≥ 23.2 and < 23.2R2-S5≥ 23.4 and < 23.4R2-S7≥ 24.2 and < 24.2R2-S2≥ 24.4 and < 24.4R2≥ 25.2 and < 25.2R2	Vulnerable	CVE Program (cve.org) e CISA ADP
Juniper Networks	Junos Os Evolved	< 22.4version 22.4version 22.4-r1version 22.4-r1-s1version 22.4-r1-s2version 22.4-r2version 22.4-r2-s1version 22.4-r2-s2 and 40 more version 22.4-r3version 22.4-r3-s1version 22.4-r3-s2version 22.4-r3-s3version 22.4-r3-s4version 22.4-r3-s5version 22.4-r3-s6version 22.4-r3-s7version 23.2version 23.2-r1version 23.2-r1-s1version 23.2-r1-s2version 23.2-r2version 23.2-r2-s1version 23.2-r2-s2version 23.2-r2-s3version 23.2-r2-s4version 23.4version 23.4-r1version 23.4-r1-s1version 23.4-r1-s2version 23.4-r2version 23.4-r2-s1version 23.4-r2-s2version 23.4-r2-s3version 23.4-r2-s4version 23.4-r2-s5version 23.4-r2-s6version 24.2version 24.2-r1version 24.2-r1-s2version 24.2-r2version 24.2-r2-s1version 24.4version 24.4-r1version 24.4-r1-s2version 24.4-r1-s3version 25.2version 25.2-r1version 25.2-r2	Vulnerable	NIST National Vulnerability Database
Juniper Networks	Junos Os Evolved	< 22.4R3-S8-EVO≥ 23.2 and < 23.2R2-S5-EVO≥ 23.4 and < 23.4R2-S7-EVO≥ 24.2 and < 24.2R2-S2-EVO≥ 24.4 and < 24.4R2-EVO≥ 25.2 and < 25.2R1-S1-EVO, 25.2R2-EVO	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

High

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
8.4	CVSS 4.0	High	—	—	sirt@juniper.net via NIST National Vulnerability Database
8.4	CVSS 4.0	High	—	—	juniper via CVE Program (cve.org) e CISA ADP
6.7	CVSS 3.1	Medium	0.8	5.9	sirt@juniper.net via NIST National Vulnerability Database
6.7	CVSS 3.1	Medium	—	—	juniper via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H (score shown at the top: sirt@juniper.net)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-78 · OS Command Injection

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.67%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Look for parameters with command/query metacharacters and unexpected child processes of the service.

endpoint telemetry (EDR)application logs

Timeline

What happened to this CVE, newest first.

2026
Affected products added · juniper networks/junos os, juniper networks/junos os evolved
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 6.7
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Apr 9, 2026 · juniper

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

2 on the record

kb.juniper.net/JSA107875
Mitigation, Vendor Advisory, vendor-advisory, NIST National Vulnerability Database
supportportal.juniper.net/JSA107875
vendor-advisory, NIST National Vulnerability Database

Elsewhere on this site

Juniper Networks
every CVE for this vendor

Injection
same class

CWE-78
other pages naming this weakness

Related CVEs (same products)

Critical CVE-2026-101982 Junos OS and Junos OS Evolved: A EVPN peer causes an rpd crash or root-level compromise when EVPN-VPWS is used 1d
High CVE-2026-102077 Junos OS: MX Series with SPC3: In a source NAT scenario malformed packets will lead to resource leaks and eventually traffic stops 1d
Critical CVE-2026-101983 Junos OS and Junos OS Evolved: An attacker causes remote code execution when J-Web virtual-domain is configured 1d
Medium CVE-2026-101964 Junos OS and Junos OS Evolved: An attacker can cause an rpd crash via a crafted LDP message 1d
Medium CVE-2026-101975 Junos OS and Junos OS Evolved: Improper OSPF LSA validation causes an rpd crash when prefix-SID best-route installation is used 1d
Medium CVE-2026-101972 Junos OS and Junos OS Evolved: Malformed OSPF packets causes routing disruption when OSPF is enabled 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-33791 is "Junos OS and Junos OS Evolved: Execution of crafted CLI commands allows for arbitrary shell injection as root", rated Medium. It affects Junos (Juniper Networks); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.7 describes technical severity. EPSS 0.67% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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