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Vulnerabilities

Vulnerability · CVE-2026-21907

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)

Published Jan 15, 2026 · catalog updated Jan 15, 2026 · Juniper Networks Junos Space

Last checked Oct 30, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-21907. EPSS is 0.20%. Act only if a listed version of Juniper Networks Junos Space is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High8.2
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.20%
Remediation
Version ranges on file
Affected products
vendor Juniper Networks Junos Space 0 <24.1R5

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Juniper Networks Junos Space 0 <24.1R50 <24.1R5

How to fix CVE-2026-21907

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-21907. EPSS is 0.20%. Act only if a listed version of Juniper Networks Junos Space is installed.

Which versions are affected?

Compare what you have installed with Juniper Networks Junos Space 0 <24.1R5 0 <24.1R5. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.20%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Juniper Junos OS security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 15, 2026 · EUVD

    Detected

    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.T

  2. Jan 15, 2026 · EUVD

    Updated

    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.T

Sources

  • CVE.orgVulnerability recordCVE-2026-21907

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-21907

    30-day exploitation probability 0.20%

    first.org
  • EUVDVulnerability recordEUVD-2026-2700

    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

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 30, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgOct 30, 2026
  • FIRST EPSSOct 30, 2026
  • EUVDOct 30, 2026