Junos OS: A low privileged user can escalate their privileges so that they can login as root

published 2026-04-09 7 mo ago modified 2026-10-26 13 d ago also EUVD-2026-21080

cvss: 7.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits: 0; none known

A UNIX Symbolic Link (Symlink) Following vulnerability in the CLI of Juniper Networks Junos OS allows a local, authenticated attacker with low privileges to escalate their privileges to root which will lead to a complete compromise of the system.

When after a user has performed a specific 'file link ...' CLI operation, another user commits (unrelated configuration changes), the first user can login as root.

This issue affects Junos OS: * all versions before 23.2R2-S7, * 23.4 versions before 23.4R2-S6, * 24.2 versions before 24.2R2-S3, * 24.4 versions before 24.4R2-S2, * 25.2 versions before 25.2R2.

This issue does not affect versions 25.4R1 or later.

Patch / fix

fixed in 1

Juniper Networks Junos OS 23.2R2-S7, 23.4R2-S6, 24.2R2-S3, 24.4R2-S2, 25.2R2, 25.4R1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 7 mo ago (2026-04-10)

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.3	CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
CNA	4.0	7.0	CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:L/AU:Y/R:U/RE:M
CNA	4.0	7.0	CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:X/RE:M/U:X

Affected products

Juniper Networks Junos OS

Classification

Weakness

CWE-61 UNIX Symbolic Link (Symlink) Following

References

kb.juniper.net /JSA107807
vendor-advisory, mitigation

Sources

CVE List CVE-2026-21916
NVD CVE-2026-21916

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary