Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-21907

Severity CVSS v4.0:
HIGH
Type:
CWE-327 Use of a Broken or Risky Cryptographic Algorithm
Publication date:
15/01/2026
Last modified:
23/01/2026

Description

A Use of a Broken or Risky Cryptographic Algorithm vulnerability in the TLS/SSL server of Juniper Networks Junos Space allows the use of static key ciphers (ssl-static-key-ciphers), reducing the confidentiality of on-path traffic communicated across the connection. These ciphers also do not support Perfect Forward Secrecy (PFS), affecting the long-term confidentiality of encrypted communications.This issue affects all versions of Junos Space before 24.1R5.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/SA:N/AU:Y/RE:M/U:Green CVSS v4.0 Severity and Metrics:

Base Score: 8.20 HIGH
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/SA:N/AU:Y/RE:M/U:Green

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): Present
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): High
Integrity (VI): None
Availability (VA): None
Confidentiality (SC): Low
Integrity (SI): None
Availability (SA): None
Automatable (AU): Yes
Vulnerability Response Effort (RE): Moderate
Provider Urgency (U): Green

Base Score 4.0
8.20
Severity 4.0
HIGH
Vector 3.x
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.90 MEDIUM
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): None
Availability (A): None

Base Score 3.x
5.90
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:juniper:junos_space:*:*:*:*:*:*:*:* 24.1 (excluding)
cpe:2.3:a:juniper:junos_space:24.1:r1:*:*:*:*:*:*
cpe:2.3:a:juniper:junos_space:24.1:r2:*:*:*:*:*:*
cpe:2.3:a:juniper:junos_space:24.1:r3:*:*:*:*:*:*
cpe:2.3:a:juniper:junos_space:24.1:r4:*:*:*:*:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools