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

> Junos Space allows static key ciphers, compromising traffic confidentiality and lacking Perfect Forward Secrecy, requiring an upgrade to fix.

- **Severity:** High 8.2 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Jan 2026
- **Updated:** 15 Jan 2026
- **Also known as:** GHSA-65rw-m955-9596

## What is CVE-2026-21907?

CVE-2026-21907 is a high-severity vulnerability in Juniper Junos Space, published on 15 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm)

## Which versions are affected by CVE-2026-21907?

It affects 1 product.


Products: Juniper Junos Space.

## How do I fix CVE-2026-21907?

No fix has been published for CVE-2026-21907 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-21907 being exploited?

There is no known exploitation of CVE-2026-21907 in the wild and no public exploit code.

## Other vulnerabilities in Juniper Junos Space

- [CVE-2014-3412](https://insights.sbomify.com/CVE-2014-3412/): Command injection in n/a (critical 10.0)
- [CVE-2014-3413](https://insights.sbomify.com/CVE-2014-3413/): Hardcoded credentials in n/a (critical 9.8)
- [CVE-2016-1265](https://insights.sbomify.com/CVE-2016-1265/): Junos Space: privilege escalation vulnerabilities in Junos Space (critical 9.8)
- [CVE-2017-10622](https://insights.sbomify.com/CVE-2017-10622/): Junos Space: Authentication bypass vulnerability (critical 9.8)
- [CVE-2016-4926](https://insights.sbomify.com/CVE-2016-4926/): Auth bypass in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-21907 and fix it if it is affected.

What it is: CVE-2026-21907 is a high-severity vulnerability in Juniper Junos Space, published on 15 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-21907 in the wild and no public exploit code.

Affected product: Juniper Junos Space. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-21907/ (Markdown: https://insights.sbomify.com/CVE-2026-21907/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-21907
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-21907
- OSV: https://osv.dev/vulnerability/CVE-2026-21907

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-21907/
Summaries are generated and may contain mistakes; the official description above is the record.