CVE-2026-21907: Junos Space: TLS/SSL server supports use of static key ciphers (ssl-static-key-ciphers)

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-15 · updated 2026-06-17
Weakness: CWE-327

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.

Affected products

Juniper Networks Junos Space: before 24.1; 24.1-r1, 24.1-r2, 24.1-r3, 24.1-r4 — fixed in 24.1

How to fix

Upgrade to a fixed version: Juniper Networks Junos Space 24.1. Check the vendor advisory for mitigations.

References

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