CVE-2026-21916
Junos OS: A low privileged user can escalate their privileges so that they can login as root
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Junos OS: A low privileged user can escalate their privileges so that they can login as root
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.
- Record
CVE-2026-21916- CVSS 4.0
- 7.0 High
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 - CVSS 3.1
- 7.3 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-61
- Updated
- 2026-11-02
EUVDEUVD-2026-21080
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.
- Record
EUVD-2026-21080- CVSS 4.0
- 7.0 High
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-x5g9-73r3-vh5h
A UNIX Symbolic Link (Symlink) Following vulnerability in the CLI of Juniper Networks Junos OS...
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.
- Record
GHSA-x5g9-73r3-vh5h- CVSS 4.0
- 7.0 High
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 - CVSS 3.1
- 7.3 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-61
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-21916- CVSS 4.0
- 7.0 High
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 - CVSS 3.1
- 7.3 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-61
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-21916 is a high vulnerability (CVSS 7.0) in Juniper Junos, published April 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.13%, the 2nd percentile. No source names a fixed version.